
Class jTli_0 



ilX", 



COFYRIC.IIT DKPOSIT. 



THE "HOW-TO-DO-IT" BOOKS 



Carpentry for Boys 

A book which treats, in a most practical and fascinating manner 
all subjects pertaining to the " King of Trades "; showing the care 
and use of tools; drawing; designing, and the laying out of work; 
the principles involved in the building of various kinds of struc- 
tures, and the rudiments of architecture. It contains over two 
hundred and fifty illustrations made especially for this work, and 
includes also a complete glossary of the technical terms used in the 
art. The most comprehensive volume on this subject ever pub- 
lished for boys. 



Electricity for Boys 

The author has adopted the unique plan of setting forth the funda- 
mental principles in each phase of the science, and practically 
applying the work in the successive stages. It shows how the 
knowledge has been developed, and the reasons for the various 
phenomena, without using technical words so as to bring it within 
the compass of every boy. It has a complete glossary of terms, and 
is illustrated with two hundred original drawings. 



Practical Mechanics for Boys 

This book takes the beginner through a comprehensive series of 
practical shop work, in which the uses of tools, and the structure 
and handling of shop machinery are set forth; how they are utilized 
to perform the work, and the manner in which all dimensional work 
is carried out. Every subject is illustrated, and model building 
explained. It contains a glossary which comprises a new system of 
cross references a feature that will prove a welcome departure in 
explaining subjects. Fully illustrated. 



Price 60 cents per volume 

THE NEW YORK BOOK COMPANY 

147 Fourth Avenue New York 



The "How-to-do-it" Books 



PRACTICAL MECHANICS FOR BOYS 



THE "HOW-TO-DO-IT" BOOKS 

PRACTICAL MECHANICS 
FOR BOYS 

In language which every boy can understand, 
and so arranged that he may readily carry 
out any work from the instructions given 

WITH MANY ORIGINAL ILLUSTRATIONS 

By J. S. ZERBE, M.E. 

AUTHOR OP 
CARPENTRY FOR BOYS ELECTRICITY FOR BOYS 




THE NEW YORK BOOK COMPANY 

New York 



<'K^ 



COPTBIOHT. 1914, BT 

THE NEW YORK BOOK COMPANY 



M -5 \^\i^ 

©C1.A376281 



CONTENTS 

Introductoby Page 1 

'^ I. On Tools Generally — Page 7 

Varied Requirements. List of Tools. Swivel Vises. 
Parts of Lathe. Chisels. Grinding Apparatus. Large 
Machines. Chucks. Bench Tools. Selecting a Lathe. 
Combination Square. Micrometers. Protractors. 
Utilizing Bevel Protractors. Truing Grindstones. Sets 
of Tools. The Work Bench. The Proper Dimensions. 
How Arranged. 

II. How TO Grind and Sharpen Tools Page 26 

Importance of the Cutting Tool. The Grinder. Cor- 
rect Use of Grinder. Lathe Bitts. Roughing Tools. 
The Clearance. The Cutting Angle. Drills. Wrong 
Grinding. Chisels. Cold Chisels. System in Work. 
Wrong Use of Tools. 

III. Setting A^■D Holding Tools Page 34 

Lathe Speed. The Hack-saw. Hack-saw Frame. The 
Blade. Files. Grindstones. Emery and Grinding 
Wheels. Carelessness in Holding Tools. Calipers. Care 
in Use of Calipers. Machine Bitts. The Proper Angle, 
for Lathe Tools. Setting the Bitt. The Setting Angle. 
Bad Practice. Proper Lathe Speeds. Boring Tools on 
Lathe. The Rake of the Drill. Laps. Using the Lap. 
Surface Gages. Uses of the Surface Gage. 



ii CONTENTS 

IV. On the First Use of the File Page 48 

The First Test. Filing an Irregular Block. Filing a 
Bar Straight. Filing Bar with Parallel Sides. Surfac- 
ing Off Disks, True Surfacing. Precision Tools. Test 
of the Mechanic. Test Suggestions. Use of the Divid- 
ers. Cutting a Key-way. Key-way Difficulties. Filing 
Metal Round. Kinds of Files. Cotter-file. Square. 
Pinion. Half-round. Round. Triangular. Equalizing. 
Cross. Slitting. Character of File Tooth. Double Cut. 
Float-cut. Rasp Cut. Holding the File. Injuring Files. 
Drawing Back the File. 

V. How TO Commence Work Page 61 

Familiarity with Tools. File Practice. Using the Di- 
viders. Finding Centers. Hack-saw Practice. Cutting 
Metal True. Lathe Work. First Steps. Setting the 
Tool. Metals Used. The Four Important Things. 
Turning Up a Cylinder. Turning Grooves. Disks. 
Lathe Speeds. 

VI. Illustrating Some of the Fundamental Devices, 

Page 68 

Belt Lacing. Gears. Crown Wheel. Grooved Friction 
Gearing. A Valve which Closes by the Water Pres- 
sure. Cone Pulleys. Universal Joint. Trammel for 
Making Ellipses. Escapements. Simple Device to Pre- 
vent a Wheel or Shaft from Turning Back. Racks and 
Pinions. Mutilated Gears. Simple Shaft Coupling. 
Clutches. Ball and Socket Joints. Tripping Devices. 
Anchor Bolt. Lazy Tongs. Disk Shears. Wabble Saw. 
Crank Motion by a Slotted Yoke. Continuous Feed by 
Motion of a Lever. Crank Motion. Ratchet Head. 



CONTENTS iii 

Bench Clamp. Helico-volute Spring. Double helico-vo- 
lute. Helical Spring. Single Volute Helix Spring. Flat 
Spiral, or Convolute. Eccentric Rod and Strap. Anti- 
dead Center for Lathe. 



VII. Properties of Materials Page 79 

Elasticity. Traction. Torsion. Flexure. Tenacity. 
The Most Tenacious Metal. Ductility. Malleability. 
Hardness. Alloys. Resistance. Persistence. Conduc- 
tivity. Equalization. Reciprocity. Molecular Forces. 
Attraction. Cohesion. Adhesion. Affinity. Porosity. 
Compressibility. Elasticity. Inertia. Momentum. 
Weight. Centripetal Force. Centrifugal Force. Cap- 
illary Attraction. The Sap of Trees. Sound. Acous- 
tics. Sound Mediums. Vibration. Velocity of Sound. 
Sound Reflections. Resonance. Echos. Speaking 
Trumpet. The Stethoscope. Tlie Vitascope. The Phon- 
autograph. The Phonograph. Light. The Corpuscular 
Theory. Undulatory Theory. Luminous Bodies. Veloc- 
ity of Light. Reflection. Refraction. Colors. The 
Spectroscope. The Rainbow. Heat. Expansion. 

VIII. How Draughting Becomes a Valuable Aid. . . .Page 95 

Lines in Drawing. Shading. Direction of Shade. Per- 
spectives. The Most Pronounced Lines. Direction of 
Light. Scale Drawings. Degree, and What it Means. 
Memorizing Angles. Section Lining. Making Ellipses 
and Irregular Curves. Focal Points. Isometric and Per- 
spective. The Protractor. Suggestions in Drawing. 
Holding the Pen. Inks. Tracing Cloth. Detail Paper. 
How to Proceed. Indicating Material by Section Lines. 



iv CONTENTS 

IX. Tbeatment and Use of Metals Page 112 

Annealing. Toughness and Elasticity. The Process. 
Tempering. Tempering Contrasted with Annealing. 
Materials Used. Gradual Tempering. Fluxing, Unit- 
ing Metals. Alloying Method. Welding. Sweating. 
Welding Compounds. Oxidation. Soldering. Soft 
Solder. Hard Solder. Spelter. Soldering Acid. The 
Soldering Iron. 

X. On Gearing, and How Ordered Page 121 

Spur and Pinion. Measuring a Gear. Pitch. Diam- 
etral Pitch. Circular Pitch. How to Order a Gear. 
Bevel and Miter Gears. Drawing Gears. Sprocket 
Wheels. 

XI. Mechanical Power Page 128 

The Lever. Wrong Inferences from Use of Lever. The 
Lever Principle. Powers vs. Distance Traveled. Power 
vs. Loss of Time. Wrongly-Directed Energy. The Lever 
and the Pulley. Sources of Power. Water Power. Cal- 
culating Fuel Energy. The Pressure or Head. Fuels. 
Power from Winds. Speed of Wind and Pressure. 
Varying Degrees of Pressure. Power from Waves and 
Tides. A Profitable Field. 

XII. On Measures Page 139 

Horse Power. Foot Pounds. Energy. How to Find Out 
the Power Developed. The Test. Calculations. The 
Foot Measure. Weight. The Gallon. The Metric Sys- 
tem. Basis of Measurement. Metrical Table, Showing 
Measurements in Feet and Inches. 



CONTENTS V 

XIII. Useful Information for the Workshop Page 148 

Finding the Circumference of a Circle. Diameter of a 
Circle. Area of a Circle. Area of a Triangle. Sur- 
face of a Ball. Solidity of a Sphere. Contents of a 
Cone. Capacity of a Pipe. Capacity of Tanks. To 
Toughen Aluminum. Amalgams. Prevent Boiler Scal- 
ing. Diamond Test. Making Glue Insoluble in Water. 
Taking Glaze Out of Grindstone. To Find Speeds of 
Pulleys. To Find the Diameters Required. To Prevent 
Belts from Slipping. Removing Boiler Scale. Gold 
Bronze. Cleaning Rusted Utensils. To Prevent Plas- 
ter of Paris from Setting Quickly. The Measurement of 
Liquids with Spoons. 

XIV. Simplicity of Great Inventions and of Nature's Man- 
ifestation Page 152 

Invention Precedes Science. Simplicity in Inventions. 
The Telegraph. Telephone. Transmitter. Phonograph. 
Wireless Telegraphy. Printing Telegraph. Electric Mo- 
tor. Explosions. Vibrations in Nature. Qualities of 
Sound. The Photographer's Plate. Quadruplex Teleg- 
raphy. Electric Harmony. Odors. Odophone. A Bou- 
quet of Vibrations. Taste. Color. 

XV. Workshop Recipes and Formulas Page 160 

Adhesives for Various Uses. Belt Glue. Cements. 
Transparent Cement. U. S. Government Gum. To 
Make Different Alloys, Bell-metal. Brass. Bronzes. 
Boiler Compounds. Celluloid. Clay Mixture for Forges. 
Modeling Clay. Fluids for Cleaning Clothes, Furniture, 
etc. Disinfectants. Deodorants. Emery for Lapping 
Purposes. Explosives. Fulminates. Files, and How to 



vi CONTENTS 

Keep Clean. Renewing Files. Fire-proof Materials or 
Substances. Floor Dressings. Stains. Foot Powders. 
Frost Bites. Glass. To Frost. How to Distinguish 
Iron and Steel. To Soften Castings. Lacquers. For 
Aluminum and Brass. Copper. Lubricants. Paper. 
Photograph}'. Plasters. Plating. Coloring Metals. 
Polishes. Putty. Rust Preventives. Solders. Solder- 
ing Fluxes. Steel Tempering. Varnishes. Sealing Wax. 

XVL Handy Tables Page 178 

Table of Weights for Round and Square Steel. Table of 
Weight of Flat Steel Bars. Avoirdupois Weight. Troy 
Weight. Apothecaries' Weight. Linear Measure. Long 
Measure. Square Measure. Solid or Cubic Measure. 
Dry Measure. Liquid Measure. Paper Measure. Table 
of Temperatures. Strength of Various Metals. Freez- 
ing Mixtures. Ignition Temperatures. Power and Heat 
Equivalents. 

XVII. Inventions and Patents, and Infokmation About the 
Rights and Duties of Inventoes and Workmen, 

Page 188 
The Machinist's Opportunities. What is an Inventor? 
Idea Not Invention. What an Invention Must Have. 
Obligation of the Model Builder. Paying for Develop- 
ing Devices. Time for Filing an Application. Selling 
an Unpatented Invention. Joint Inventors. Joint 
Owners Not Partners. Partnerships in Patents. Form 
of Protection Issued by the Government. Life of a 
Patent. Interference Proceedings. Concurrent Appli- 
cations. Granting Interference. Steps in Interference. 
First Sketches. First Model. First Operative Machine. 



CONTENTS vii 

Preliminary Statements. Proving Invention. What 
Patents Are Issued For. Owner's Rights. Divided and 
Undivided Patents. Assignments. How Made. What 
an Invention Must Have. Basis for Granting Patent in 
the United States. Reasons for Granting Abroad. 
Original Grants of Patents. International Agreement. 
Application for Patents. Course of Procedure. Costs. 
Filing a Matter of Secrecy. 



t 
34 



LIST OF ILLUSTRATIONS 

FIG. PACK 

1. Bench vise 8 

2. Pipe grip for vise 9 

3. Swivel vise * 10 

4. Speed lathe 11 

5. Calipers 12 

6. Engine lathe 13 

7. Center gage ^ 14 

8. Pocket screw and wire gage 15 

9. Handy bench vise 1(> 

10. Combination square 17 

11. Uses of the combination square LS 

12. A quick adjusting micrometer . 19 

13. Universal bevel protractor 20 

14. Uses of universal bevel protractor 21 

15. Grindstone truing device 22 

16. Set of tools and case 23 

17. The work bench 24 

18. Hook tool 28 

19. Parting tool 28 

20. Knife tool 28 

21. Eight-hand side tool 28 

22. Internal tool . 28 

23. Left-hand side tool 28 

24. Tool for wrought iron 29 

25. Tool for cast iron 29 

26. End view of drill 31 

27. Side view of drill 31 

28. Hack-saw frame 35 

29. Hack-saw blade 35 

30. Plain hook tool 38 

31. Plain straight tool 38 

32. Proper angles for tools 39 

33. Angles for tools 39 

ix 



X LIST OF ILLUSTRATIONS 

FIG. PAGE 

34. Angles for tools 39 

35. Set of the bitt 40 

30. Correct angle 41 

37. Wrong angle 41 

38. Too low 42 

39. Improper set 42 

40. Internal set 43 

41. Set for brass 43 

42. Surface gage 44 

43. Uses of surface gage 46 

44. Hounded surface 49 

45. Winding surface 49 

46. Hexagon nut 51 

47. Laying off hexagon nut 51 

48. Cutting key-way 52 

49. Key-seat rule 54 

50. Filing metal round 54 

51. Filing metal round 54 

52. Making a round bearing 55 

53. Making a round bearing 55 

54. Cross section of file 56 

55. Files 58 

56. Correct file movement 59 

57. Incorrect file movement 60 

58. Belt lacing 69 

59. Belt lacing 69 

60. Belt lacing 69 

61. Belt lacing 69 

62. Bevel gears 71 

63. Miter gears 71 

64. Crown wheel 71 

65. Grooved friction gears 71 

06. Valve . 71 

67. Cone pulleys 71 

68. Universal joint 71 

69. Trammel 73 

70. Escapement 73 

71. Device for holding wheel 73 



LIST OF ILLUSTRATIONS xx 

FIG. PAGE 

72. Rack and pinion 73 

73. Mutilated gears 73 

74. Shaft coupling 73 

75. Clutches 75 

76. Ball and socket joints 75 

77. Fastening ball 75 

78. Tripping devices 75 

79. Anchor bolt 75 

80. Lazy tongs 75 

81. Disc shears 75 

82. Wabble saw 76 

83. Continuous crank motion 76 

84. Continues feed 76 

85. Crank motion 76 

86. Ratchet head 76 

87. Bench clamp 76 

88. Helico-volute spring 77 

89. Double helico-volute 77 

90. Helical spring 77 

91. Single volute-helix 77 

92. Flat spiral or convolute 77 

93. Eccentric rod or strap 77 

94. Anti dead-centers for lathes 77 

95. Plain circle 95 

96. Ring 96 

97. Raised surface 96 

98. Sphere 96 

99. Depressed surface 96 

100. Concave 97 

101. Forms of cubical outlines 98 

102. Forms of cubical outlines 98 

103. Forms of cubical outlines 98 

104. Forms of cubical outlines 98 

105. Shading edges 90 

106. Shading edges 90 

107. Illustrating heavy lines 100 

108. Illustrating hea\^ lines 100 

109. Lines on plain surfaces 101 



xii LIST OF ILLUSTRATIONS 

FIG. PAGE 

110. Lines on plain surfaces 101 

111. Illustrating degrees 102 

112. Section lining 103 

113. Drawing an ellipse 104 

114. Perspective at angles 106 

115. Perspective of cube 107 

116. Perspective of cube 107 

117. Perspective of cube 107 

118. Protractor 108 

119. Using the protractor 109 

120. Section-lining metals 110 

121. Spur gears 122 

122. Miter gear pitch 123 

123. Bevel gears 124 

124. Laying of miter gears 125 

125. Sprocket wheel 126 

126. Simple lever 129 

127. Lever action 130 

128. The pulley 132 

129. Change of direction 133 

130. Change of direction 133 

131. Steam pressure 135 

132. Water pressure 135 

133. Prony brake 141 

134. Speed indicator 142 



PRACTICAL MECHANICS FOR BOYS 



INTRODUCTORY 

The American method of teaching the mechani- 
cal arts has some disadvantages, as compared 
with the apprentice system followed in England, 
and very largely on the continent. 

It is too often the case that here a boy or a 
yonng man begins work in a machine shop, not for 
the avowed purpose of learning the trade, but 
simply as a helper, with no other object in view 
than to get his weekly wages. 

Abroad, the plan is one which, for various rea- 
sons, could not be tolerated here. There he is 
bound for a certain term of years, and with the 
prime object of teaching him to become an arti- 
san. More often than otherwise he pays for this 
privilege, and he knows it is incumbent on him 
*'to make good" right from the start. 

He labors under the disadvantage, however, that 
he has a certain tenure, and in that course he 
is not pushed forward from one step to the next 
on account of any merit of his own. His advance- 
ment is fixed by the time he has put in at each 

1 



2 PEACTICAL MECHANICS FOE BOYS 

part of the work, and thus no note is taken of his 
individuality. 

Here the boy rises from step to step by virtue 
of his own qualifications, and we recognize that 
one boy has the capacity to learn faster than 
another. If he can learn in one year what it re- 
quires three in another to acquire, in order to 
do it as perfectly, it is an injury to the apt work- 
man to be held back and deterred from making his 
way upwardly. 

It may be urged that the apprentice system 
instills thoroughness. This may be true; but it 
also does another thing: It makes the man a 
mere machine. The true workman is a thinker. 
He is ever on the alert to find easier, quicker and 
more perfect means for doing certain work. 

What is called "Efficiency" in labor methods, 
can never obtain in an apprenticeship system for 
this reason. In a certain operation, where twelve 
motions are required to do a certain thing, and 
a minute to perform the twelve operations, a sim- 
plified way, necessitating only eight motions, 
means a difference in saving one-third of the time. 
The nineteen hundred fewer particular move- 
ments in a day's work, being a less strain on the 
operator, both physically and mentally, to say 
nothing whatever of the advantages which the 
proprietor of the shop would gain. 



INTRODUCTORY 3 

I make this a leading text in the presentation 
of this book; namely, that individual merit and 
stimulus is something of such extreme importance 
that it should be made the keynote for every boy 
who tries to become a mechanic. 

The machinist easily occupies a leading place 
in the multitude of trades and occupations. 
There is hardly an article of use but comes to 
the market through his hands. His labor is most 
diverse, and in his employment doing machine 
work he is called upon to do things which vary 
widely in their character. 

These require special knowledge, particular 
tools, and more frequently than otherwise, a high 
order of inventive ability to enable him to accom- 
plish the task. 

The boy should be taught, at the outset, that 
certain things must be learned thoroughly, and 
that habits in a machine shop can be bad as well 
as good. When he once becomes accustomed to 
putting a tool back in its rightful place the mo- 
ment he is through with it, he has taken a long 
step toward efficiency. 

When he grasps a tool and presents it to the 
work without turning it over several times, or 
has acquired the knack of picking up the right 
tool at the proper place, he is making strides in 



4 PEACTICAL MECHANICS' FOE BOYS 

the direction of becoming a rapid and skilled 
workman. 

These, and many other things of like import, 
will require our attention throughout the vari- 
ous chapters. 

It is not the intention of the book to make every 
boy who reads and studies it, a machinist; nor 
have we any desire to present a lot of useful arti- 
cles as samples of what to make. The object is 
to show the boy what are the requirements neces- 
sary to make him a machinist ; how to hold, handle, 
sharpen and grind the various tools; the proper 
ones to use for each particular character of work ; 
how the various machines are handled and cared 
for; the best materials to use; and suggest the 
numerous things which can be done in a shop 
which will pave the way for making his work 
pleasant as well as profitable. 

It also analyzes the manner in which the job is 
laid out ; how to set the tools to get the most eifec- 
tive work; and explains what is meant by making 
a finished piece of workmanship. These things, 
properly acquired, each must determine in his 
own mind whether he is adapted to follow up the 
work. 

Over and above all, we shall try to give the 
boy some stimulus for his work. Unless he 
takes an interest in what he is doing, he will 



INTRODUCTORY 5 

never become an artisan in the true sense of the 
word. 

Go through the book, and see whether, here and 
there, you do not get some glimpses of what it 
means to take a pleasure in doing each particular 
thing, and you will find in every instance that 
it is a satisfaction because you have learned to 
perform it with ease. 

I do not know of anything which has done as 
much to advance the arts and manufactures, dur- 
ing the last century, as the universal desire to im- 
prove the form, shape and structure of tools ; and 
the effort to invent new ones. This finds its re- 
flection everywhere in the production of new and 
improved products. 

In this particular I have been led to formulate 
a homely sentence which expresses the idea : In- 
vention consists in doing an old thing a new way ; 
or a new thing any old way. 

The Authoe. 



CHAPTER I 

ON TOOLS GENEKALLY 

Judging from tlie favorable comments of edu- 
cators, on the general arrangement of tlie subject 
matter in the work on ^^Carpentry for Boys," I 
am disposed to follow that plan in this book in 
so far as it pertains to tools. 

In this field, as in "Carpentry," I do not find 
any guide which is adapted to teach the boy the 
fundamentals of mechanics. Writers usually 
overlook the fact, that as the boy knows nothing 
whatever about the subject, he could not be ex- 
pected to know anything about tools. 

To describe them gives a start in the education, 
but it is far short of what is necessary for one in 
his condition. If he is told that the chisel or bit 
for a lathe has a diamond point, or is round-nosed, 
and must be ground at a certain angle, he natu- 
rally wants to know, as all boys do, ivhy it should 
be at that angle. 

So in the setting of the tools with relation of 
the work, the holding and manipulation of the 
file, of the drill for accurate boring, together with 
numerous little things, are all taken for granted, 
and the boy blunders along with the ultimate ob- 

7 



8 PEACTICAL MECHANICS FOE BOYS 

ject in sight, without having the pathway cleared 
so he may readily reach the goal. 

Vaeied Eequikemexts. — The machinist's trade 
is one which requires that most varied tools of 




I^tgJ.M]^ ^^•^g. 



all occupations, and they are by all odds the most 
expensive to be found in the entire list of voca- 
tions. 

This arises from the fact that he must work 
with the most stubborn of all materials. He finds 
resistance at every step in bringing forth a prod- 
uct. 

List of Tools. — With a view of familiarizing 



ON TOOLS GENERALLY 



9 



the boy with this great variety the following list 
is compiled, from which we shall select the ones 
essential in the initial equipment of a small shop. 
Vises. — One small, good vise is infinitely pref- 
erable to two bad ones. For ordinary work a 3- 
inch jaw is preferable, and it should be firmly 
mounted on the bench. So many kinds are now 
made that it would be a costly thing to purchase 





-7^. ^. Bm ^^P dormt. 



one for each special use, therefore the boy will 
find it profitable to make some attachments for 
the ordinary vise. 

Swivel Vises. — A swivel vise is always a good 
tool, the cost being not excessive over the ordi- 
nary kind. Then a pair of grips for holding pipe, 
or round material which is to be threaded, can 
readily be made. 

The drawing (Fig. 2) shows a serviceable pair 
of grips, made to fit the jaws of a vise, and will 



10 PEACTICAL MECHANICS FOE BOYS 

be acceptable in much of the work. Then, the 
vise should be provided with copper caps for the 
jaws to be used when making up articles which 
would otherwise be injured by the jaws. 




1^.3. ^ti^iirel . l/'Ue 



Let us get a comprehensive view of the different 
kinds of tools necessary in a fully equipped shop. 

Parts of Lathe. — The first thing of importance 
is the lathe, and of these there is quite a variety, 
and among the accompaniments are the slide rest, 
mandrel, back" gear, division plate, angle plate, 
cone plate and various chucks. 



ON TOOLS GENEEALLY 



11 



There must also be change wheels, studs and 
quadrant plates, self-acting feed for surfacing 
and cross slide, and clamping nuts. 

Drilling machines, both hand and power, hand 
and ratchet braces and breast-drill stocks. 




Fig. k. — B'peed Lathe. 

Chisels. — Chisels of various kinds, for chip- 
ping and cross-cutting; round-nosed, centering, 
set punches, tommies and drifts. 

Back, tee and centering square; bevels, spirit 
level, inside and outside calipers, straight edges, 
rules and surface plates. 

35 / 



12 PEACTICAL MECHANICS FOE BOYS 

Gages for boring, scribing blocks, steel and 
brass scribes, stocks and dies, screw-plates, taps 
for bolts, reamers. 




OufAtde 



r^.^. 



Tn^tcle 



Files for various descriptions, countersinks, 
frame and hack saws. 

Grinding Apparatus. — Emery wheel, cloth and 
paper, paper, flour emery, polishing powders, laps 
and buffs, and polishing sticks. 



ON TOOLS GENERALLY 



13 




14 PEACTICAL MECHANICS FOR BOYS 

Forge, anvils, tongs, swages, punches, bolt tools, 
hot and cold chisels, blow-pipe, soldering iron, 
hard and soft solders, borax, spirits of salts, oil, 
resin and spelter. 

To this may be added an endless variety of 
small bench tools, micrometers, protractors, ar- 
bors, collets, box tools and scrapers. 

Lakge MACHi]^rEs. — The list wonld not be com- 
plete without the planer, shaper and milling ma- 




JTig. 7 Center Ca^. 



chine, with their variety of chucks, clamps and 
other attachments, too numerous to mention. 

The foregoing show what a wonderful variety 
of articles are found in a well-equipped shop, all 
of which can be conveniently used; but to the 
boy who has only a small amount of money, a 
workable set is indicated as follows : 

A small lathe, with an 8-inch swing, can be 
obtained at a low cost, provided with a counter- 
shaft complete. 

Chucks. — With this should go a small chuck. 



ON TOOLS GENERALLY 15 

and a face-plate for large work, unless a large 
chuck can also be acquired. This, with a dozen 
tools of various sizes, and also small bits for 
drilling purposes. 

The lathe will answer all purposes for drilling, 
but small drilling machines are now furnished at 
very low figures, and such a machine will take 
off a great deal of duty from the lathe. 

As the lathe is of prime importance, never use 



lS§S?S?$S^?5^J^=5-k.»^^ 



-Z^^^ 6. Pocket ^crcu/ and U/'^inGa^e. 



it for drilling, if you have a driller, as it always 
has enough work to do for tuning up work. 

Bench Tools. — Of bench tools, a 3-inch vise, 
various files, center punch, two hammers, round 
and A-shaped peons, hack saw^ compasses, inside 
and outside calipers, screw driver, cold chisels, 
metal square, level, straight edge, bevel square, 
reamers, small emery wheel and an oil stone, make 
a fairly good outfit to start with, and these can 
be added to from time to time. 

Everything in the machine shop centers about 



16 PEACTICAL MECHANICS FOR BOYS 

the lathe. It is the king of all tools. The shaper 
and planer may be most efficient for surfacing, 
and the milling machine for making grooves and 
gears, or for general cutting purposes, but the 
lathe possesses a range of work not possible with 




JIandij Bench Vi6e , 



either of the other tools, and for that reason 
should be selected with great care. 

Selecting a Lathe. — The important things 
about a lathe are the spindle bearings and the 
ways for the tool-holder. The least play in either 
will ruin any work. Every other part may be 



ON TOOLS GENEKALLY 



17 



defective, but with solidly built bearing-posts and 
bearings, your lathe will be effective. 

For this reason it will not pay to get a cheap 
tool. Better get a small, 6-inch approved tool 
of this kind, than a larger cheap article. It may 
pay with other tools, but with a lathe never. 

Never do grinding on a lathe. The fine emery, 
or grinding material, is sure to reach the bear- 




Fig. 10. — Combination Square. 



ings ; it matters not what care is exercised. There 
is only one remedy for this — overhauling. 

Combination Square. — A tool of this kind is 
most essential, however small. It can be used as 
a try-square, and has this advantage, that the 
head can be made to slide along the rule and be 
clamped at any point. It has a beveling and a 
leveling device, as well. 

The combination square provides a means for 



18 PEACTICAL MECHANICS FOE BOYS 




Fig. 11. — Uses of the Combination Square. 



ON TOOLS GENERALLY 



19 



doing a great variety of work, as it combines tlie 
qualities of a rule, square, miter, depth gage, 
height gage, level and center head. 

The full page illustration (Fig. 11) shows some 




Fig. 12. — A Quick Adjusting Micrometer. 



of the uses and the particular manner of holding 
the tool. 

Micrometers. — Tools of this description are 
made which will accurately measure work in di- 



20 PEACTICAL MECHANICS FOR BOYS 

mensions of ten-thousandths of an inch up to an 
inch. 

The illustration (Fig. 12) shows an approved 
tool, and this is so constructed that it can instantly 
be changed and set by merely pressing the end 
of the plunger as shown. 




Fig. 13. — A Universal Bevel Protractor. 



Protractoes. — As all angles are not obtainable 
by the square or bevel, a protractor is a most 
desirable addition to the stock of tools. As one 
side of the tool is flat it is convenient for laying 
on the paper when drafting, as well as for use 
on the work. 

The protractor has a graduated disk, and is 
adjustable so it can be disposed at any angle. 



ON TOOLS GENEEALLY 



21 




Fig. IJf. — Universal Bevel Protractor, showing its uses. 



22 PEACTICAL MECHANICS FOR BOYS 

All special tools of this kind are serviceable, 
and the boy should understand their uses, even 
though he is not able for the time being to acquire 
them. To learn how they are applied in daily 
use is an education in itself. 

Utilizing Bevel Peoteactor. — Examine the 
full-page illustration (Fig. 14), and see how the 



Fig. 15. — Grindstone Truing Device. 

bevel protractor is utilized to measure the angles 
of work, whether it is tapering heads or different 
kinds of nuts, or end and side surfacing, and 
it will teach an important lesson. • 

Truing Grindstones. — Devices for truing up 
grindstones are now made, and the illustration 
(Fig. 15) shows a very efficient machine for this 
purpose. It can be applied instantly to the face 



ON TOOLS GENERALLY 



23 



of the stone, and it works automatically, without 
interfering with the use of the stone. 

It is frequently the case that an emery wheel 
will become glazed, due to its extreme hardness. 
This is also caused, sometimes, by running it at 




Fig. 16.— Set of Tools and Case. 



too high a speed. If the glazing continues after 
the speed is reduced, it should be ground down 
an eighth of an inch or so. This will, usually, 
remedy the defect. 

Sets of Tools. — A cheap and convenient set of 



24 PEACTICAL MECHANICS FOR BOYS 

precision tools is shown in Fig. 16, which is kept 
in a neat folding leather case. The set consists 
of a 6-inch combination square, complete center 
pnnch, 6-inch flexible steel rule center gage, 4-inch 
calipers, 4-inch outside caliper with solid nut, 
4-inch inside caliper with solid nut, and a 4-inch 
divider with a solid nut. 




I^ig. 17. T'Tmmork^^nch. 



The Work Bench. — This is the mechanic's fort. 
His capacity for work will depend on its arrange- 
ment. To the boy this is particularly interesting, 
and for his uses it should be made full three inches 
lower than the standard height. 

A good plan to judge of the proper height is 
to measure from the jaws of the vise. The top 
of the jaw should be on a level with the elbows. 
Grasp a file with both hands, and hold it as though. 



ON TOOLS GENEEALLY 25 

in tlie act of filing across the work ; then measure 
Tip from the floor to the elbows, when they are 
held in that position. 

The Proper Dimensions. — This plan will give 
you a sure means of selecting a height that is best 
adapted for your work. The regulation bench is 
about 38 inches high, and assuming that the vise 
projects up about 4 inches more, would bring the 
top of the jaws about 42 to 44 inches from the 
floor. It is safe to fi^ the height of the bench at 
not less than 34 inches. 

This should have a drawer, preferably near the 
right-hand end of the bench. The vise should be 
at the left side, and the bench in your front should 
be free of any fixed tools. 

How Arranged. — Have a rack above the bench 
at the rear, for the various tools when not in use, 
and the rear board of the bench should be elevated 
above the front planks several inches, on which 
the various tools can be put, other than those 
which are suspended on the rack above. 

The advantage of this is, that a bench will ac- 
cumulate a quantity of material that the tools can 
hide in, and there is nothing more annoying than 
to hunt over a lot of trash to get what is needed. 
It is necessary to emphasize the necessity of al- 
ways putting a tool back in its proper place, im- 
mediately after using. 



CHAPTER II 

HOW TO GRIND AND SHARPEN TOOLS 

It is singular, that with the immense variety 
of tools set forth in the preceding chapter, how 
few, really, require the art of the workman to 
grind and sharpen. If we take the lathe, the drill- 
ing machine, as well as the shaper, planer, milling 
machine, and all power-driven tools, they are 
merely mechanism contrived to handle some small, 
and, apparently, inconsequential tool, which does 
the work on the material. 

Importance of the Cutting Tool. — But it is 
this very fact that makes the preparation of that 
part of the mechanism so important. Here we 
have a lathe, weighing a thousand pounds, worth 
hundreds of dollars, concentrating its entire ener- 
gies on a little bit, weighing eight ounces, and 
worth less than a dollar. It may thus readily 
be seen that it is the little bar of metal from 
which the small tool is made that needs our care 
and attention. 

This is particularly true of the expensive mill- 
ing machines, where the little saw, if not in per- 
fect order, and not properly set, will not only 
do improper work, but injure the machine itself. 

26 



TO GRIND AND SHARPEN TOOLS 27 

More lathes are ruined from using badly ground 
tools than from any other cause. 

In the whole line of tools which the machinist 
must take care of daily, there is nothing as im- 
portant as the lathe cutting-tool, and the knowl- 
edge which goes with it to use the proper one. 

Let us simplify the inquiry by considering them 
under the following headings : 

1. The grinder. 

2. The grinding angle. 

The Gkindee. — The first mistake the novice will 
make, is to use the tool on the grinder as though, 
it were necessary to grind it down with a few 
turns of the wheel. Haste is not conducive to 
proper sharpening. As the wheel is of emery, 
corundum or other quickly cutting material, and 
is always run at a high rate of speed, a great 
heat is evolved, which is materially increased by 
pressure. 

Pressure is injurious not so much to the wheel 
as to the tool itself. The moment a tool becomes 
heated there is danger of destroying the temper, 
and the edge, being the thinnest, is the most vio- 
lently affected. Hence it is desirable always to 
have a receptacle with water handy, into which 
the tool can be plunged, during the process of 
grinding down. 

Correct Use of Grinder. — Treat the wheel as. 

36 



28 PEACTICAL MECHANICS FOE BOYS 

thougli it is a friend, and not an enemy. Take 
advantage of its entire surface. Whenever you 
go into a machine shop, look at the emery wheel. 
If you find it worn in creases, and distorted in 
its circular outline, you can make up your mind 
that there is some one there who has poor tools, 
Ibecause it is simply out of the question to grind 
a tool correctly with such a wheel. 



^ ^^ ^ 






J^l^. /S. ParUn^ Tool . 2^. ^^. TntBTTudTool 

y J A ———— 



^ =^ 

jrtg.^O. Knife 2hol. J^ ^d. LeFirhiirtd UdeTM. 

Coarse wheels are an abomination for tool work. 

Use the finest kinds devised for the purpose. 
They will keep in condition longer, are not so 
liable to wear unevenly, and will always finish 
oif the edge better than the coarse variety. 

Lathe Bits. — All bits made for lathes are modi- 
:fications of the foregoing types (Figs. 18, 19, 20, 
21, 22, 23). 

As this chapter deals with the sharpening meth- 
ods only, the reader is referred to the next chap- 



TO GEIND AND SHARPEN TOOLS 29 

ter, which deals with the manner of setting and 
holding them to do the most effective work. 

When it is understood that a cutting tool in a 
lathe is simply a form of wedge which peels off 
a definite thickness of metal, the importance of 
proper grinding and correct position in the lathe 
can be appreciated. 

EouGHiNG Tools. — The most useful is the 
roughing tool to take off the first cut. As this 





I I I I 



1^7jj p.4 Tnq] -fnT rjh-nu^taiDn . Tlg.^. Tool for Cattirtnu 

type of tool is also important, with some modifi- 
cations, in finishing work, it is given the place of 
first consideration here. 

Fig. 24 shows side and top views of a tool de- 
signed to rough off wrought iron, or a tough qual- 
ity of steel. You will notice, that what is called 
the top rake (A) is very pronounced, and, as the 
point projects considerably above the body of the 
tool itself, it should, in practice, be set with its 
cutting point above the center. 



30 PEACTICAL MECHANICS FOR BOYS 

The Clearance. — Now, in grinding, the impor- 
tant point is the clearance line (B). As shown in 
this figure, it has an angle of 10 degrees, so that 
in placing the tool in the holder it is obvions it 
cannot be placed very high above the center, par- 
ticularly when used on small work. The top rake 
is ground at an angle of 60 degrees from the ver- 
tical. The arc of the curved end depends on the 
kind of lathe and the size of the work. 

The tool (Fig. 25), with a straight cutting edge, 
is the proper one to rough oif cast iron. Note 
that the top rake (C) is 70 degrees, and the clear- 
ance 15 degrees. 

The Cutting Angle. — ^Wrought iron, or mild 
steel, will form a ribbon when the tool wedges its 
way into the material. Cast iron, on the other 
hand, owing to its brittleness, will break off into 
small particles, hence the wedge surface can be 
put at a more obtuse angle to the work. 

In grinding side-cutters the clearance should 
be at a less angle than 10 degrees, rather than 
more, and the top rake should also be less ; other- 
wise the tendency will be to draw the tool into 
the work and swing the tool post around. 

Deills. — Holders for grinding twist drills are 
now furnished at very low prices, and instructions 
are usually sent with the machines, but a few 
words may not be amiss for the benefit of those 



TO GRIND AND SHARPEN TOOLS 31 

who have not the means to purchase such a 
machine. 

Hand grinding is a difficult thing, for the reason 
that through carelessness, or inability, both sides 
of the drill are not ground at the same angle and 
pitch. As a result the cutting edge of one side 
will do more work than the other. If the heel 




PART . 

angles differ, one side will draw into the work, and 
the other resist. 

Wrong Grinding. — When such is the case the 
hole becomes untrue. The sides of the bit will 
grind into the walls, or the bit will have a tendency 
to run to one side, and particularly if boring 
through metal which is uneven in its texture or 
grain. 

Figs. 26 and 27 show end and side views of a 
bit properly ground. If a bit has been broken 
off, first grind it off square at the end, and then 
grind down the angles, so that A is about 15 de- 
grees, and be sure that the heel has sufficient 



32 PEACTICAL MECHANICS FOR BOYS 

clearance — that is, ground down deeper than the 
cutting point. 

Chisels. — A machine shop should always have 
a plentiful supply of cold chisels, and a particular 
kind for each work, to be used for that purpose 
only. This may seem trivial to the boy, but it is 
really a most important matter. 

Notice the careless and incompetent workman. 
If chipping or cutting is required, he will grasp 
the first chisel at hand. It may have a curved 
end, or be a key-way chisel, or entirely unsuited 
as to size for the cutting required. 

The result is an injured tool, and unsatisfac- 
tory results. The rule holds good in this respect 
as with every other tool in the kit. Use a tool for 
the purpose it was made for, and for no other. 
Acquire that habit. 

Cold Chisels. — A cold chisel should never be 
ground to a long, tapering point, like a wood 
chisel. The proper taper for a wood chisel is 15 
degrees, whereas a cold chisel should be 45 de- 
grees. A drifting chisel may have a longer taper 
than one used for chipping. 

It is a good habit, particularly as there are so 
few tools which require grinding, to commence the 
day's work by grinding the chisels, and arranging 
them for business. 

System in Wokk. — Then see to it that the drills 



TO GEIND AND SHAEPEN TOOLS 33 

are in good shape; and while you are about it, 
look over the lathe tools. You will find that it 
is better to do this work at one time, than to go 
to the emery wheel a dozen times a day while you 
are engaged on the job. 

Adopt a system in your work. Don't take 
things just as they come along, but form your 
plans in an orderly way, and you will always know 
how to take up and finish the work in the most 
profitable and satisfactory way. 

Wrong Use of Tools. — Never use the vise as 
an anvil. Ordinary and proper use of this tool 
will insure it for a lifetime, aside from its natural 
wear. It may be said with safety that a vise will 
never break if used for the purpose for which it 
was intended. One blow of a hammer may- 
ruin it. 

Furthermore, never use an auxiliary lever to 
screw up the jaws. If the lever which comes 
with it is not large enough to set the jaws, you may 
be sure that the vise is not large enough for your 
work. 



CHAPTER III 

SETTING AND HOLDING TOOLS 

Some simple directions in the holding and set- 
ting of tools may be of service to the novice. Prac- 
tice has shown the most effective way of treating 
different materials, so that the tools will do the 
most efficient work. 

A tool ground in a certain way and set at a par- 
ticular angle might do the work admirably on a 
piece of steel, but would not possibly work on alu- 
minum or brass. 

Lathe Speed. — If the lathe should run at the 
same speed on a piece of cast iron as with a brass 
casting, the result would not be very satisfactory, 
either with the tool or on the work itself. 

Some compositions of metal require a high speed, 
and some a hooked tool. These are things which 
each must determine as the articles come to the 
shop; but there are certain well-defined rules with 
respect to the ordinary metals that should be ob- 
served. 

The Hack Saw. — Our first observation should 
be directed to the hand tools. The hack saw is one 
of the most difficult tools for the machinist to han- 
dle, for the following reasons : 

34 



SETTING AND HOLDING TOOLS 35 

First, of the desire to force the blade through 
the work. The blade is a frail instrument, and 
when too great a pressure is exerted it bends, and 
as a result a breakage follows. To enable it to 
do the work properly, it must be made of the hard- 
est steel. It is, in consequence, easily fractured. 




Fig. 28. — Each Saw Frame. 




ri'P- ^ 






Fig. 29.— Hack Saw Blade. 



Second. The novice will make short hacking 
cuts. This causes the teeth to stick, the saw bends, 
and a new^ blade is required. Take a long sweeping 
cut, using the entire length of the blade. Do not os- 
cillate the blade as you push it through the work, 
but keep the tooth line horizontal from one end of 
the stroke to the other. The moment it begins to 
waver, the teeth will catch on the metal on the side 
nearest to you, and it will snap. 



36 PEACTICAL MECHANICS FOE BOYS 

Third. The handle is held too loosely. The 
handle must be firmly held with the right hand, 
and the other held by the fingers lightly, but in 
such a position that a steady downward pressure 
can be maintained. If loosely held, the saw is 
bound to sag from side to side during the stroke, 
and a short stroke accentuates the lateral move- 
ment. A long stroke avoids this. 

The hack saw is one of the tools which should be 
used with the utmost deliberation, combined with 
a rigid grasp of the handle. 

Files. — For remarks on this tool see Chapter IV, 
which treats of the subject specially. 

Gkindstones, Emery and Grinding Wheels. — 
A good workman is always reflected by his grind- 
ing apparatus. This is true whether it has refer- 
ence to a grindstone, emery, corundum wheel, or a 
plain oil stone. Nothing is more destructive of 
good tools than a grooved, uneven, or wabbly stone. 
It is only little less than a crime for a workman 
to hold a tool on a revolving stone at one spot. 

Carelessness in Holding Tools. — The boy must 
learn that such a habit actually prevents the proper 
grinding, not only of the tool he has on the stone, 
but also of the one which follows. A\niile it is true 
that all artificially made grinders will wear uneven- 
ly, even when used with the utmost care, due to 
uneven texture of the materials in the stone, still, 



SETTING AND HOLDING TOOLS 37 

the careless use of the tool, while in the act of 
grinding, only aggravates the trouble. 

Another fault of the careless workman is, to 
press the bit against the stone too hard. This cuts 
the stone more than it wears off the tool, and it is 
entirely unnecessaiy. Furthermore, it heats up 
the tool, which should be avoided. 

Calipees. — A true workman, who endeavors to 
turn out accurate work, and preserve his tools, will 
never test the work with his calipers while the piece 
is turning in the lathe. A revolving cast iron disk 
will cut ruby, the hardest substance next to the 
diamond, so it is not the hardness of the material 
which resists wear, but the conditions under which 
it is used. 

Caee in Use of Calipers. — The calipers may 
be of the most hardened steel, and the work turned 
up of the softest brass, the latter, when revolving, 
will grind off the point of the tool, for the reason 
that the revolving piece constantly presents a new 
surface to the point of the calipers, and when tests 
are frequently made, it does not take long to change 
the caliper span so that it must be reset. 

As stated elsewhere, the whole energy of the 
lathe is concentrated on the bit or cutting tool, 
hence, in order to get the most effective work out 
of it requires care ; first, in grinding ; and, second, 
in settins:. 



38 PEACTICAL MECHANICS FOE BOYS 

Machine Bits. — It does not always matter so 
much whether you use a square, pointed, or a 
round-nosed bit, provided it is properly ground and 
set in the tool holder. As a rule, the more brittle 
the metal the less the top rake or angle should be. 

In the chapter relating to the grinding of tools, 
references were made as to the most serviceable 
bits for the various metals. We are concerned here 
with the setting or holding of these articles. 




] c 



I 



J 



Plain Hook Tool Plain Straight Tool 

The two illustrations here given show a pair of 
plain bits, in which Fig. 30 represents a hook- 
shaped formation, and Fig. 31 a straight grind, 
without any top rake. The hooked bit would do 
for aluminum, or steel, but for cast iron the form 
shown in Fig. 31 would be most sjerviceable. 

Then the side bits, such as the round-nosed, Fig. 
32 and the square end. Fig. 33, may be ground 
hooked, or with a top rake, or left flat. 

The too common mistake is to grind the lower 
or clearance side at too great an angle. Fig. 34 



SETTING AND HOLDING TOOLS 39 

shows the correct angle, and the dotted line A illus- 
trates the common tendency to grind the clearance. 
The Pijopek Angle foe Lathe Tools. — Now 
there is a reason why the angle of from 10 to 15 
should he maintained in the clearance. The point 
of the tool must have suitable support for the work 
it is required to do, so it will not chatter or yield 



(7- 




"7 



Trover Angles fcyr Tools 

in the slightest degree. A bit ground along the 
dotted line has a cutting edge which will spring 
down, and consequently break or produce a rough 
surface. 

Then, again, the angle of the clearance acts as a 
guide, or rather, a guard, to prevent the tool from 
going in too far, as will now be explained. 

Setting the Bit. — In order to understand the 
correct setting, examine the work A, in Fig. 35. 

A is a cylinder being turned up in the lathe, and 
B the cutting tool, which approaches it on a hori- 



40 PEACTICAL MECHANICS FOR BOYS 

zontal line, C, extending out from the center of the 
cylinder A. This setting is theoretically correct, 
and in practice has been found most advantageous. 

In this case let us assume that the clearance angle 
D is 15 degrees, as well as in the following figures. 

Suppose we have a piece of tough steel, and the 
tool holder is raised so that the point of the tool 
is at the 15 degree line E, as shown in Fig. 36, in 




Set of the Bit 

which case the clearance line D is at right angles 
to the line E. The line E is 15 degrees above the 
center line C. 

The Setting Angle. — Now, it is obvious that if 
the tool should be raised higher than the line E it 
would run out of work, because the clearance sur- 
face of the tool would ride up over the surface cut 
by the edge of the tool. 

If, on the other hand, the tool should be placed 
lower, toward the line C, the tendency would be to 
draw in the tool toward the center of the work A. 



SETTING AND HOLDING TOOLS 41 

In Fig. 37 the tool has its point elevated, in 
which case it must he lowered so the point will touch 
the work nearer the center line C. 

The foregoing arrangement of the tools will be 
found to he effective where the material is soft and 
not too tough as with aluminum. 

Bad Pkactice. — Figs. 38 and 39 show illustra- 
tions of had practice which should never he resorted 




F'tg.de. 

Correct Angle 



Wrong Angle 



to. Fig. 38 shows the tool, held in a horizontal po- 
sition, hut with its point below the center line C. 
With any rough metal the tool could not possibly 
work, except to act as a scraper, and if it should 
be used in that position on cast iron, the tool itself 
would soon be useless. 

Fig. 39 is still worse, and is of no value for any 
purpose except in polishing brass, where it would 
be serviceable. It would make a sorry looking job 
with aluminum. Brass requires a tool with very 



42 PEACTICAL MECHANICS FOR BOYS 

little top rake, and the point should be set near the 
center line C. 

Lathe Speed. — It is often a question at what 
speeds to run the lathe for different work. If you 
know the speeds of your lathe at low and high gear, 
you must also consider the diameter of the work 
at the cutting point. 

The rule is to have the bit cut from 15 to 20 feet 
per minute for wrought iron ; from 11 to 18 feet for 




Too Low 



Im'pro'per Set 



steel ; from 25 to 50 for brass ; and from 40 to 50 
for aluminum. 

As a result, therefore, if, at low speed, a piece 
10 inches in diameter, runs at the proper speed to 
cut at that distance from the center, it is obvious 
that a piece 5 inches in diameter should run twice 
as fast. This is a matter which time and practice 
will enable you to judge with a fair degree of ac- 
curacy. 



SETTING AND HOLDING TOOLS 43 

Observe this as a maxim: "Slow speed, and 
quick feed." 

Boeing Tools on Lathe. — The lathe is a most 
useful tool for boring purposes, better, for some 
work than the drilling machine itself. The work 
which can be done better on a lathe than on a 
drilltQg machine, may be classified as follows : 

1. When straight and true holes are required. 





Internal Set Set for Brass 

2. In long work, where the lathe is used to turn 
up the article, and where the drilling can be done 
at the same time. 

3. Anything that can be chucked in a lathe. 

4. Where the work is long and cannot be fixed 
in a drilling machine. The long bed of the lathe 
gives room for holding such work. 

The Rake of the Deill. — ^A boring tool requires 
some knowledge in setting. It should have a 
greater top rake than for the outside work, and the 
cutting edge should also be keener, as a rule. 

37 



44 PEACTICAL MECHANICS FOE BOYS 




Fig. Ji-2. — Surface Gage. 



In this class of work the material bored must be 
understood, as well as in doing outside work. 

The hooked tool, Fig. 40, is shown to be consider- 
ably above the center line, and at that point it will 
do the most effective cutting on steel. If, on the 
other hand, brass is operated on there should be no 



SETTING AND HOLDING TOOLS 45 

top rake, as illustrated in Fig. 41, thus assuring 
a smooth job. 

Laps. — This is a tool which is very useful, par- 
ticularly for grinding and truing up the cylinders 
of internal combustion engines, as well as for all 
kinds of bores of refractory material which can- 
not be handled with the cutting tool of the lathe. 

It is made up of a mandrel or rod of copper, with 
lead cast about it, and then turned up true, so that 
it is but the merest trifle larger than the hole it is 
to true up. 

Using the Lap. — ^The roller thus made is turned 
rapidly in a lathe, and the cylinder to be trued 
is brought up to it and the roller supplied freely 
with emery powder and oil. As rapidly as possible 
the cylinder is worked over on the roller, without 
forcing it, and also turned, so as to prevent even 
the weight from grinding it unduly on one side. 

More or less of the emery will embed itself in 
the lead, and thus act as an abrasive. The process 
is called " lapping." 

Surface Gages. — Frequently, in laying out, it is 
necessary to scribe lines at a given distance from 
some part of the work ; or, the conditions are such 
that a rule, a caliper, or dividers will not permit 
accurate measurement to be made. 

For such purposes, what is called a surface gage 
was devised. This is merely a heavy base, provid- 



46 PEACTICAL MECHANICS FOE BOYS 




Fig. JfS. — Showing uses of the Surface Gage. 



SETTING AND HOLDING TOOLS 47 

ed with a pivoted upright on which is mounted a 
scrihe that is held by a clamp so it may be turned 
to any angle. 

SuKFACE Gage. — The clamp holding the scriber 
is vertically movable on the pivoted upright. By 
resting the base of the surface gage on the line to 
be measured from, and swinging one point of the 
scriber to the place where the work is to be done, 
accuracy is assured. One end of the scriber is bent, 
so it can be adapted to enter recesses, or such places 
as could not be reached by the straight end. 



CHAPTER lY 

ON THE USE OP THE FILE 

The most necessary tool in a machine shop is 
a file. It is one of the neglected tools, because the 
ordinary boy, or workman, sees nothing in it bnt a 
strip or a bar mth a lot of cross grooves and edges, 
and he concludes that the only thing necessary is to 
rub it across a piece of metal until he has worn it 
down sufficiently for the purpose. 

The FniST Test. — The fact is, the file is so fa- 
miliar a tool, that it breeds contempt, like many 
other things closely associated in life. 

Give the boy an irregular block of metal, and 
tell him to file it up square, and he will begin to 
realize that there is something in the handling of 
a file that never before occurred to him. 

He will find three things to astonish him : 

First : That of dimensions. 

Second : The difficulty of getting it square. 

Third : The character of the surface when he has 
finished it. 

Filing an Ieregulab Block. — To file a block of 
an irregular character so that the dimensions are 
accurate, is a good test for an accomplished work- 
man. The job is made doubly difficult if he is re- 
quired to file it square at the same time. It will 

48 



ON THE USE OF THE FILE 49 

be found, invariably, that the sides will not be par- 
allel, and by the time it is fully trued up the piece 
will be too small. See Figs. 44 and 45. 

Then, unless the utmost care is taken, the flat 
sides will not be flat, but rounded. 

Filing a Bar Straight. — The next test is to get 
the boy to flLle a bar straight. He has no shaper 
or planer for the purpose, so that it must be done 
by hand. He will find himself lacking in two 



Rounded Surface A Winding Face 

things: The edge of the bar will not be straight; 
nor will it be square with the side of the bar. 

Filing Bar with Parallel Sides. — Follow up 
this test by requiring him to file up a bar, first, 
with two exactly parallel sides, and absolutely 
straight, so it mil pass smoothly between the legs 
of a pair of calipers, and then file the two other 
sides in like manner. 

Surfacing off Disks. — When the foregoing are 
completed there is still another requirement which, 
though it appears simple, is the supreme test. Set 
him to work at surfacing off a pair of disks or 
plates, say one and a half inches in diameter, so 



50 PEACTICAL MECHANICS FOR BOYS 

that when they are finished they will fit against each 
other perfectly flat. 

A pair of such disks, if absolutely true, will hold 
together by the force of cohesion, even in a dry 
state, or they will, as it were, float against each 
other. 

Tkue SuEFACiisrG. — Prior to about 1850 the ne- 
cessity of true surfacing was not so important or 
as well known as at the present time. About that 
period Sir J. Whitworth, an eminent English engi- 
neer and mechanic, called the attention of machin- 
ists to the great advantage arising from true sur- 
faces and edges for all types of machinery, and he 
laid the foundation of the knowledge in accurating 
surfacing. 

Peecisiok Tools. — Due to his energy many pre- 
cision tools were made, all tending to this end, and 
as a result machines became better and more effi- 
cient in every way. 

It had this great advantage : It taught the work- 
man of his day how to use the file and scraper, be- 
cause both must be used conjunctively to make an 
absolutely flat plate. 

Contrary to general beliefs, shapers and planers 
do not make absolutely accurate surfaces. The test 
of this is to put together two plates so planed off. 
There is just enough unevenness to permit air to 
get between the plates. If they were perfectly true 



\ 



ON THE USE OF THE FILE 



51 



they would exclude all air, and it would be a diffi- 
cult matter to draw them apart. 

Test of the Mechanic. — To make them perfect- 
ly flat, one plate has chalk rubbed over it, and the 
two plates are then rubbed together. This will 
quickly show where the high spots are, and the file 
and scraper are then used to cut away the metal. 





JTig.^S. 



7^^,4Z 



Hexagon Nut 



In England the test of the mechanic used to be 
determined by his ability to file a piece of metal 
flat. It was regarded as the highest art. This is 
not the most desirable test at the present time, 
and it is recognized that a much severer test is to 
file a narrow piece exactly flat, and so that it will 
not have a trace of roundness, and be square from 
end to end. 

Test Suggestions. — ^In a shop which does not 
have the advantage of a planer or shaper, there 



52 PEACTICAL MECHANICS FOE BOYS 

are so many articles which must be filed up, that it 
is interesting to know something of how the various 
articles are made with a file. 

To file a hexagon, or six-sided nut will be a good 
test with a file. To do this a little study in geomet- 
rical lines will save a vast amount of time. In be- 
ginning the work, measure the radius with a divid- 




Cutting Key-way 

er, and then step off and make six marks equi- 
distant from each other on the round surface. 

Use of the Dividees. — The distance between each 
of these points is equal to the radius, or half the 
diameter, of the round bar. See Fig. 46, which 
shows this. The marks should be scribed across 
the surface, as shown in Fig. 47, where the lines 
show the ends of the facets of the outside of the 
nut. 

Do not let the file obliterate the lines at the rough 



ON THE USE OF THE FILE 53 

cutting, but leave enongli material so you can make 
a good finish at the line. 

Cutting a Key- way. — Another job you may have 
frequent occasion to perform, is to cut a way for 
a key in a shaft and in a wheel hub. Naturally, 
this will be first roughed out with a cold chisel nar- 
rower than the key is to be, and also slightly shal- 
lower than the dimensions of the key. 

A flat file should be used for the purpose, first 
a heavy rough one, for the first cutting. The bet- 
ter way is to have the key so it can be frequently 
tried while the filing process is going on, so that 
to fit the key in this way is a comparatively easy 
task. 

Key-way Difficulties. — ^But the trouble com- 
mences when the groove is filed for the depth. 
Invariably, the mistake will be made of filing the 
width first, so the key will fit in. As a result, in 
deepening the groove the file will contact with the 
walls, and you have a key-way too wide for the 
key. 

To avoid this, file the depth, or nearly so, and 
then with a fine file cut in the corners in the direc- 
tion indicated by the dart A, Fig. 48. 

A proper key is square in cross section. In such' 
a case the depth of the key- way, at each side wall, 
is just half the width of the key-way. 

An excellent key-seat rule can be made by filing 



54 PEACTICAL MECHANICS FOE BOYS 

out two right-angled pieces, as shown in Fig. 49, 
which can be attached to the ordinary six-inch 
metal rule, and this will enable you to scribe the 
line accurately for the key-way on the shaft. 




'jrig,4^9. Key-6e€ti : Itude 




Filing Metal Round 

Filing Metal Round. — It is sometimes neces- 
sary to file a piece of metal round. This is a hard 
job, particularly where it is impossible to scribe 
the end of the piece. Suppose it is necessary to 
file up a bearing surface, or surfaces, intermediate 
the ends of a square bar. 

You have in that case four sides to start from, 



*i 



ON THE USE OF THE FILE 



55 



the opposite sides being parallel with each other, 
so that you will have two dimensions, and four 
equal sides, as shown in Fig. 50. 

The first step will be to file off accurately the 
four corners 1, 2, 3, 4, so as to form eight equal 
sides or faces, as shown in Fig. 51. If you will 
now proceed to file down carefully the eight cor- 
ners, so as to make sixteen sides, as in Fig. 52, the 




Making a Bar Round 

fourth set of corners filed down will make the filed 
part look like the illustration Fig. 53 with thirty- 
two faces. 

This may be further filed down into sixty-four 
faces, and a few cuts of the finishing ^e will take 
off the little ridges which still remain. By using 
emery cloth, and wrapping it around the bearing 
portion, and changing it continually, while drawing 



56 PEACTICAL MECHANICS FOE BOYS 



it back and forth, will enable you to make a bear- 
ing which, by care, will caliper up in good shape. 

Kinds of Files. — Each file has five distinct 
properties; namely: the length, the contour, the 
form in cross section, the kind of teeth, and the 
fineness of the teeth. 

There are nine well-defined shapes for files. 
These may be enumerated as follows : 



B 



UPOADO 

S 4 6 6 7 8 



No. 1. The cotter file. The small kind is called 
a verge or pivot file. 

No. 2. Square file, which may be tapering from 
end to end, or have parallel sides throughout. 

No. 3. Watch pinion file. This may have its 
sides parallel or tapering, to make a knife-shaped 
file. 

No. 4. Half-round; which may be used for 
either nicking, piecing, or rounding-off purposes. 

No. 5. Eound, with parallel sides for gulleting 
purposes, or rat-tail when it tapers. 

No. 6. Triangular, or three equally-sided body 
for saw filing. 



ON THE USE OF THE FILE 57 

No. 7. Equalizing file. This is parallel when 
used for making clock-pinions or endless screws; 
or for slitting, entering, warding, or making bar- 
rel holes, when the body of the file tapers. 

No. 8. Cross, or double-round, half -file. 

No. 9. Slitting file; which has parallel sides 
only. A cant file. 

Chaeactek of the File Tooth. — Files are dis- 
tingTiished principally by the character of the ob- 
lique, or cross grooves and ridges which do the 
cutting and abrading when the file is drawn across 
the surface. 

This is really more important than the shape, 
because the files, by their cuttings, are adapted for 
the various materials which they are to be used 
upon. 

The files are classified as Double Cut, of which 
there are the rough, middle, bastard, second cut, 
smooth, and dead smooth. 

The Float Cut, which is either rough, bastard or 
smooth; and 

The Rasp Cut, either rough, bastard or smooth. 

Several tj^es are illustrated in Fig. 55, which 
show the characteristics of the various cuts. 

The rasps are used principally for soft material, 
such as wood or for hoofs, in horse shoeing, hence 
they need not be considered in connection with 
machine-shop work. 



58 PEACTICAL MECHANICS FOE BOYS 







ON THE USE OF THE FILE 



59 



Holding the File. — The common mistake on the 
part of the beginner is to drag the file across the 
work at an angle. The body of the file should move 
across straight and not obliquely. 

Note this movement in Fig. 56 where the dash 
shows the correct movement of the file with rela- 



n. 



TTTjTTTTTTTnjr 



n 



YJ 



Correct File Movement 

tion to the work. Also observe that the file cutting 
ridges are not straight across the file, but at an 
angle to the direction of the dart. 

Injuring Files. — Now the frequent practice is 
to use the file as shown in Fig. 57, in which case 
it is moved across obliquely. The result is that the 
angle of the file cut is so disposed that the teeth 
of the file do not properly aid in the cutting, but 
in a measure retard the operation. 

File teeth are disposed at an angle for the pur- 



60 PEACTICAL MECHANICS FOE BOYS 

pose of giving them a shearing cut, which is the 
case when the file moves across the work on a line 
with its body. 

To use a file as shown in Fig. 57 injures the file 
without giving it an opportunity to cut as fast as 
it would when properly used. 




Incorrect File Movement 



Drawing Back the File. — In drawing hack a 
file it is always better to allow it to drag over the 
work than to raise it up. It is frequently the case 
that some of the material will lodge in the teeth, 
and the back lash will serve to clear out the grooves. 

This is particularly true in filing copper, alu- 
minum, lead, and like metals, but it is well to ob- 
serv^e this in all cases. 



CHAPTER V 

HOW TO COMMENCE WOEK 

The question is often asked: Where and how 
shall the novice commence work 1 

^Alien the shop is equipped, or partially so, suf- 
ficient, at least, to turn out simple jobs, the boy will 
find certain tools which are strangers to him. He 
must become acquainted with them and not only 
learn their uses, but how to use them to the best 
advantage. 

Familiarity with Tools. — Familiarity with the 
appearance of tools, and seeing them in the hands 
of others will not be of any value. Nothing but the 
immediate contact with the tool will teach how to 
use it. 

File Pkactice. — The file is a good tool to pick 
up first. Select a piece of metal, six or eight inches 
long, and follow the instructions laid down in the 
chapter relating to the use of the file. 

Practice with several kinds and with different 
varieties of material will soon give an inkling of 
the best kind to use with the metal you have. Use 
the straight edge and the square while the filing 
process is going on, and apply them frequently, 

61 



62 PEACTICAL MECHANICS FOR BOYS 

to show you what speed you are making and how 
nearly true you are surfacing up the piece. 

Using the Divideks. — Then try your hand using 
the dividers, in connection with a centering punch. 
As an example, take two pieces of metal, each 
about a foot long, and set the dividers to make a 
short span, say an inch or so, and step off the 
length of one piece of metal, and punch the last 
mark. Then do likewise with the other piece of 
metal, and see how nearly alike the two measure- 
ments are hy comparing them. 

You will find a variation in the lengths of the 
two measurements at the first trials, and very like- 
ly will not be able to make the two pieces register 
accurately after many trials, even when using the 
utmost care. 

Sooner or later you will learn that you have not 
stepped paths along the two bars which were ex- 
actly straight, and this will account for the varia- 
tions. In order to be accurate a line should be 
drawn along each piece of metal, and the dividers 
should step off the marks on that line. 

Finding Centers. — By way of further experi- 
ment, it might be well to find the exact center of 
the ends of a square bar, putting in the punch 
marks and then mounting it in the lathe centers to 
see how accurately this has been done. 

If either end is out of true the punch marks can 



HOW TO COMMENCE WORK 63 

be corrected by inclining tlie punch, so that when it 
is struck it will move over the point in the direction 
of its true center. This may be followed up by cen- 
tering the end of a round bar so as to make it true. 
This will be found to be a more difficult job, unless 
you have a center head, a tool made for that 
purpose. 

It is good practice, however, to make trials of 
all this work, as it will enable you to judge of meas- 
urements. It can be done with the dividers by us- 
ing care in scribing the centers. 

Hack-Saw Practice. — Practice with the hack- 
saw should be indulged in frequently. Learn to 
make a straight cut through a bar. Try to do this 
without using a square to guide you. One of the 
tests of a good mechanic is ability to judge a 
straight cut. 

The following plan is suggested as a test for the 
eye. Use a bar of iron or steel one inch square, and 
make a cut an eighth of an inch deep across it; 
then turn it around a quarter, so as to expose the 
next face, and continue the cut along the side, the 
same depth, and follow this up with the remaining 
two sides, and see how near the end of the first cut 
and the finish cut come together. The test will 
surprise you. 

Cutting Metals True. — When you saw off the 
end of such a bar for trial purposes, use a square. 



64 PEACTICAL MECHANICS FOR BOYS 

after the cut is made, and note how much it is out 
of true in both directions. It is a curious fact that 
most mechanics are disposed to saw or cut crooked 
in one direction, either to the right or to the left. 
In tests made it is found that this defect is per- 
sisted in. 

It is practice only which will remedy this, and 
it would be well for the boy to learn this for him- 
self as early in his career as possible, and correct 
the tendency to veer in either direction. 

The test of sawing around a round bar is also 
commended. After a few trials you will be sur- 
prised to see how your judgment will improve in 
practice. 

Lathe Work. — Learn the uses of the chuck. As 
you have, probably, economized as much as possi- 
ble, a universal chuck is not available, hence the 
first experience will be with an independent chuck, 
where the three dogs move independently of each 
other. This will give you some work to learn how 
you can get the job true. 

Now, before attempting to cut the material, thor- 
oughly learn all the parts of the feed mechanism, 
and how to reverse, as well as to cross feed. Learn 
the operation of the operative parts so that your 
hand will instinctively find them, while the eye is 
on the work. 

First Steps. — See to it that your tools are sharp, 



HOW TO COMMENCE WOEK 65 

and at tlie first trials make light cuts. Practice 
the feeds by manually moving the tool holder, for 
surface cutting as well as for cross cutting. 

Setting the Tool. — Set the cutting tool at vari- 
ous angles, and try the different tools, noting the 
peculiarities of each, at the different speeds. Do 
not, by any means, use refractory metals for your 
first attempt. Mild steel is a good test, and a light 
gray iron is admirable for practice lessons. 

Metals Used. — Brass is good for testing pur- 
poses, but the difficulty is that the tendency of the 
boy, at first, is to try to do the work too rapidly, 
and brass encourages this tendency. Feed slowly 
and regularly until you can make an even finish. 

Then chuck and re-chuck to familiarize yourself 
with every operative part of the lathe, and never 
try to force the cutting tool. If it has a tendency 
to run into the work, set it higher. If, on the other 
hand, you find, in feeding, that it is hard to move 
the tool post along, the tool is too high, and should 
be lowered. 

The Fouk Important Things. — Constant prac- 
tice of this kind will soon enable you to feel in- 
stinctively when the tool is doing good work. 
While you are thus experimenting do not forget the 
speed. This will need your attention. 

Eemember^ you have several things to think 
about in commencing to run the lathe, all of which 



66 PEACTICAL MECHANICS FOR BOYS 

will take care of themselves when it becomes fa- 
miliar to you. These may be enumerated as fol- 
lows: 

First : The kind of tool best to use. 

Second : Its proper set, to do the best work. 

Third: The speed of the work in the lathe. 

Fourth: The feed, or the thickness of the cut 
into the material. 

Turning up a Cylinder. — The first and most im- 
portant work is to turn up a small cylinder to a 
calipered dimension. When it is roughed down 
ready for the finish cut, set the tool so it will take 
off a sufficient amount to prevent the caliper from 
spanning it, and this will enable you to finish it 
off with emery paper, or allow another small cut 
to be taken. 

Turning Grooves. — Then follow this up by turn- 
ing in a variety of annular grooves of different 
depths and widths ; and also V-shaped grooves, the 
latter to be performed by using both the longi- 
tudinal and transverse feeds. This will give you 
excellent practice in using both hands simulta- 
neously. 

The next step would be to turn out a bore and 
fit a mandrel into it. This will give you the op- 
portunity to use the caliper to good advantage, and 
will test your capacity to use them for inside as 
well as for outside work. 



HOW TO COMMENCE WORK 67 

Discs. — A job that will also afford good exercise 
is to turn up a disc with a groove in its face, and 
then chuck and turn another disk with an annular 
rib on its face to fit into the groove. This requires 
delicacy of measurement with the inside as well as 
the outside calipers. 

The groove should be cut first, and the measure- 
ment taken from that, as it is less difficult to handle 
and set the tool for the rib than for the groove. 

Lathe Speeds. — Do not make the too common 
mistake of running the mandrel at high speeds in 
your initial tests. It is far better to use a slow 
speed, and take a heavy cut. This is good advice 
at all times, but it is particularly important with 
beginners. 



CHAPTEE VI 

ILLUSTKATING SOME OF THE FUNDAMENTAL DEVICES 

Theke are numerous little devices and shop ex- 
pedients which are desirable, and for which the 
boy will find uses as he progresses. 

We devote this chapter to hints of this kind, all 
of which are capable of being turned out or util- 
ized at various stages. 

Lacing Belts. — To properly lace a belt is quite 
an art, as many who have tried it know. If a belt 
runs off the pulley it is attributable to one of thr-ee 
causes: either the pulleys are out of line or the 
shafts are not parallel or the belt is laced so it 
makes the belt longer at one margin than the 
other. 

In Fig. 58 the lacing should commence at the 
center hole (A) of one belt end and lace outward- 
ly, terminating at the hole (B) in the center of the 
other belt end, as shown in Fig. 58. 

In Fig. 59 the lacing commences at A, and ter- 
minates at the hole (B) at the edge. This will be 
ample for all but the widest belts. 

Fig. 60 is adapted for a narrow belt. The lac- 
ing commences at one margin hole (A), and ter- 
minates at the other margin hole (Z). 



FUNDAMENTAL DEVICES 



69 



Fig. 61 shows the outside of the belt. 

Fig. 62. Geaes. — This is something every boy 
ought to know about. Fig. 62 shows a pair of 
intermeshing bevel gears. This is the correct term 
for a pair when both are of the 
same diameter. 



MiTEK Geaks. — In Fig. 63 we 



TnUde, JP^Z/^.Sia. 




have a pair of miter gears, one 
being larger than the other. 
Eemember this distinction. 

Fig. 64. Ckowi^ Wheel. — 
This is a simple manner of 
transmitting motion from one 
shaft to another, when the 
shafts are at right angles, or 
nearly so, without using bevel 
or miter gears. 

Fig. 65. Gkooved Feiction 
Geaeing. — Two grooved pul- 
leys, w^hich fit each other accu- 
rately, will transmit power 
without losing too much by 
friction. The deeper the 
grooves the greater is the loss 
by friction. 

Fig. QQ. A Valve "Which Closes by the Watee 
Peessuee. — The bibb has therein a movable valve 
on a horizontal stem, the valve being on the inside 



c« 





^ 




=9' 


/f^i^. Sii 



ZT^.eo 




jf^.6/ 



70 PEACTICAL MECHANICS FOR BOYS 

of the seat. The stem of the handle has at its 
lower end a crank bend, which engages with the 
outer end of the valve stem. When the handle is 
turned in either direction the valve is unseated. 
On releasing the handle the pressure of the water 
against the valve seats it. 

Fig. 67. Cone Pulleys. — Two cone pulleys of 
equal size and taper provide a means whereby a 
change in speed can be transmitted from one shaft 
to another by merely moving the belt to and fro. 
The slightest change is available by this means. 

Fig. 68. Univeksal Joint. — A wheel, with four 
projecting pins, is placed between the U-shaped 
yokes on the ends of the approaching shafts. 
The pins serve as the pivots for the angles formed 
by the two shafts. 

Fig. 69. Trammel for Making an Ellipse. — 
This is a tool easily made, which will be of great 
service in the shop. In a disc (A), preferably 
made of brass, are two channels (B) at right 
angles to each other. The grooves are undercut, 
so that the blocks (C) will fit and slide in the 
grooves and be held therein by the dove-tailed for- 
mation. Each block is longer than the width of 
the groove, and has an outwardly projecting pin 
which passes through a bar (D). One pin (E) is 
movable along in a slot, but is adjustable at any 
point so that the shape of the ellipse may be 



FUNDAMENTAL DEVICES' 



71 



varied. The end of the bar has 
a series of holes (G) for a pen- 
cil, so th^t the size of the el- 
lipse may also be changed. 

Fig. 70. Escapements. — 
Various forms of escapements 
may be made, but the object of 
all is the same. The device is 
designed to permit a wheel to 
move intermittingly or in a step 
by step movement, by the 
swinging motion of a pendulum. 
Another thing is accomplished 
by it. The teeth of the escape- 
ment are cut at such an angle 
that, as one of the teeth of the 
escapement is released from 
one tooth of the escapement 
wheel, the spring, or the weight 
of the clock, will cause one of 
the teeth of the escapement 
wheel to engage the other tooth 
of the escapement, and give the 
pendulum an impulse in the 
other direction. In the figure, 
A is the escapement, B the es- 
capement wheel, and a, b, the 




2^.6;e. 




:F%g.es. 



NWiiillll'illliillilii 



:r^64 




1^^.66 




T^vgez 




j?^.^a 



72 PEACTICAL MECHANICS FOE BOYS 

pallets, which are cut at suitable angles to actuate 
the pendulum. 

Fig. 71. Simple Device to Pkevent a Wheel or 
Shaft fkom Turning Back. — This is a substitute 
for a pawl and ratchet wheel. A is a drum or 
a hollow wheel and B a pulley on a shaft, and this 
pulley turns loosely with the drum (A). Four 
tangential slots (C) are cut into the perimeter of 
the pulley (B), and in each is a hardened steel 
roller (D). It matters not in what position the 
wheel (B) may be, at least two of the rollers will 
always be in contact with the inside of the drum 
(A), and thus cause the pulley and drum to turn 
together. On reversing the direction of the pulley 
the rollers are immediately freed from binding con- 
tact. 

Fig. 72. Eacks and Pinions.— The object of 
this form of mechanism is to provide a recipro- 
cating, or back-and-forth motion, from a shaft 
which turns continually in one direction. A is the 
rack and B a mutilated gear. When the gear 
turns it moves the rack in one direction, because 
the teeth of the gear engage the lower rack teeth, 
and when the rack has moved to the end its teeth 
engage the teeth of the upper rack, thus reversing 
the movement of the rack. 

Fig. 73. Mutilated Gears. — These are made 
in so many forms, and adapted for such a 



FUNDAMENTAL DEVICES 



73 



Tariety of purposes, that we 
merely give a few samples to 
show what is meant by the 
term. 

Fig. 74. Simple Shaft 
Coupling. — Prepare two simi- 
larly formed discs (A, B), 
which are provided with hubs 
so they may be keyed to the 
ends of the respective shafts. 
One disc has four or more pro- 
jecting pins (C), and the other 
disc suitable holes (D) to re- 
ceive the pins. 

Fig. 75. Clutches. — This is 
a piece of mechanism which is 
required in so many kinds of 
machinery, that we show sev- 
eral of the most approved 
types. 

Fig. 76. Ball and Socket 
Joints. — The most practical 
form of ball and socket joints 
is simply a head in which is a 
bowl-shaped cavity the depth of 
one-half of the ball. A plate 
with a central opening small 
enough to hold in the ball, and 




jrig£9. 




JFYg.70 




:r6g.7J 




jri^.7^ 




ITY^.TQ 







JF7^.7^ 



74 PEACTICAL MECHANICS FOE BOYS 

still large enough at the neck to permit the arm 
carrying the ball to swing a limited distance, is 
secured by threads, or by bolts, to the head. The 
first figure shows this. 

Fig. 77 illustrates a simple manner of tighten- 
ing the ball so as to hold the standard in any de- 
sired position. 

Fig. 78. Tkipping Devices. — These are usually 
in the form of hooks, so arranged that a slight 
pull on the tripping lever will cause the suspended 
articles to drop. 

Fig. 79. Anchok Bolt. — These are used in brick 
or cement walls. The bolt itself screws into a 
sleeve which is split, and draws a wedge nut up to 
the split end of the sleeve. As a result the split 
sleeve opens or spreads out and binds against 
the wall sufficiently to prevent the bolt from being 
withdrawn. 

Fig. 80. Lazy Tongs. — One of the simplest and 
most effective instruments for carrying ice, boxes 
or heavy objects, which are bulky or inconven- 
ient to carry. It grasps the article firmly, and the 
heavier the weight the tighter is its grasp. 

Fig. 81. Disc Sheaes. — This is a useful tool 
either for cutting tin or paper, pasteboard and the 
like. It will cut by the act of drawing the mate- 
rial through it, but if power is applied to one or to 
both of the shafts the work is much facilitated, 



FUNDAMENTAL DEVICES 



75 



particularly in thick or hard 
material. 

Fig. 82. Wabble Saw. — 
This is a most simple and use- 
ful tool, as it will readily and 
quickly saw out a groove so 
that it is undercut. The saw 
is put on the mandrel at an 
angle, as will be seen, and 
should be run at a high rate of 
speed. 

Fig. 83. Ceaitk Motion by a 
Slotted Yoke. — This produces 
a straight back-and-f orth 
movement from the circular 
motion of a wheel or crank. 
It entirely dispenses with a pit- 
man rod, and it enables the 
machine, or the part of the 
machine operated, to be placed 
close to the crank. 

Fig. 84. Continuous Feed 
BY THE Motion of a Levee. — 
The simple lever with a pawl 
on each side of the fulcrum is 
the most effective means to 
make a continuous feed by the 
simple movement of a lever, 
The form shown is capable of 

39 




zrig,76 




JE^.77 





JFYg.TB 




:z^&g.so 




76 PEACTICAL MECHANICS FOE BOYS 




•JTigMS 




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many modifications, and it can 
be easily adapted for any par- 
ticular work desired. 

Fig. 85. Ckank Motion. — ' 
By tlie structure shown, name- 
ly, a slotted lever (A), a quick 
return can be made with tbe 
lever. B indicates the fulcrum. 

Fig. '^^. Eatchet Head. — 
This shows a well-known form 
for common ratchet. It has 
the advantage that the radially 
movable plugs (A) are tan- 
gentially disposed, and rest 
against walls (B) eccentrically 
disposed, and are, therefore, in 
such a position that they easily 
slide over the inclines. 

Fig. 87. Bench Clamp. — 'K 
pair of dogs (A, B), with the 
ends bent toward each other, 
and pivoted midway between 
the ends to the bench in such 
a position that the board (C), 
to be held between them, on 
striking the rear ends of the 
dogs, will force the forward 
ends together, and thus clamp 



FUNDAMENTAL DEVICES 



77 



it firmly for planing or other 
purposes. 

Fig. 88. H E L I c o - Volute 
Sprtn^g.— This is a form of 
spring for tension purposes. 
The enlarged cross-section of 
the coil in its middle portion, 
with the ends tapering down 
to the eyes, provides a means 
whereby the pull is transferred 
from the smaller to the larger 
portions, without produciag a 
great breaking strain near the 
ends. 

Fig. 89. Double Helico- 
VoLUTE. — This form, so far as 
the outlines are considered, is 
the opposite of Fig. 88. A 
compression spring of this 
kind has a very wide range of 
movement. 

Fig. 90. Helical SpEma. — 
This form of coil, uniform 
from end to end, is usually 
made of metal which is square 
in cross-section, and used 
where it is required for heavy 
purposes. 




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78 PEACTICAL MECHANICS FOE BOYS 

Fig, 91. Single Volute Helix-Speing. — This 
is also used for compression, intended where tre- 
mendous weights or resistances are to be over- 
come, and when the range of movement is small. 

Fig. 92. Flat Spiral, or Convolute. — This is 
for small machines. It is the familiar form used 
in watches owing to its delicate structure, and it 
is admirably adapted to yield to the rocking mo- 
tion of an arbor. 

Fig. 93. EccENTEic EoD AND Steap. — A simple 
and convenient form of structure, intended to fur- 
nish a reciprocating motion where a crank is not 
available. An illustration of its use is shown on 
certain types of steam engiae to operate the 
valves. 

Fig. 94. Anti-Dead Centee for Foot-Lathes. — 
A flat, spiral spring (A), with its coiled end at- 
tached to firm support (B), has its other end 
pivotally attached to the crank-pin (C), the ten- 
tion of the spring being such that when the lathe 
stops the crack-piQ will always be at one side of 
the dead-center, thus enabling the operator to 
start the machiae by merely pressing the foot 
downwardly on the treadle (D). 



CHAPTER VII 

PEOPERTIES OF MATEEIALS 

A WORKMAN is able to select tlie right metals 
because he knows that each has some peculiar 
property which is best adapted for his particular 
use. These with their meaning will now be ex- 
plained. 

Elasticity. — This exists in metals in three dis- 
tinct ways : First, in the form of traction. Hang 
a weight on a wire and it will stretch a certain 
amount. When the weight is removed the wire 
shrinks back to its original length. 

Second: If the weight on the wire is rotated^ 
so as to twist it, and the hand is taken from the 
weight, it will untwist itself, and go back to its 
original position. This is called torsion. 

Third : A piece of metal may be coiled up like 
a watch spring, or bent like a carriage spring, 
and it will yield when pressure is applied. This 
is called flexure. 

Certain kinds of steel have these qualities in a 
high degree. 

Tenacity. — This is a term used to express the 
resistance which the body opposes to the separa- 
tion of its parts. It is determined by forming 

79 



80 PEACTICAL MECHANICS FOR BOYS 

the metal into a wire, and hanging on weights, 
to find how much will be required to break it. If 
we have two wires, the first with a transverse area 
only one-qnarter that of the second, and the first 
breaks at 25 pounds, while the second breaks at 
50 pounds, the tenacity of the first is twice as 
great as that of the second. 

To the boy who understands simple ratio in 
mathematics, the problem would be like this : 

25 X 4 : 50 X 1, or as 2 : 1. 

The Most Tenacious Metai.. — Steel has the 
greatest tenacity of all metals, and lead the least. 
In proportion to weight, however, there are many 
substances which have this property in a higher 
degree. Cotton fibers will support millions of 
times their own weight. 

There is one peculiar thing, that tenacity varies 
with the form of the body. A solid cylindrical 
body has a greater strength than a square one of 
the same size ; and a hollow cylinder more tenacity 
than a solid one. This principle is well known in 
the bones of animals, in the feathers of birds, 
and in the stems of many plants. 

In almost every metal tenacity diminishes as 
the temperature increases. 

Ductility. — This is a property whereby a metal 
may be drawn out to form a wire. Some metals, 



PEOPEETIES OF MATERIALS 81 

like cast iron, have absolutely no ductility. The 
metal which possesses this property to the highest 
degree, is platinum. Wires of this metal have 
been drawn out so fine that over 30,000 of them 
laid side by side would measure only one inch 
across, and a mile of such wire would weigh only 
a grain, or one seven-thousandth of a pound. 

JMalleability. — This is considered a modifica- 
tion of ductility. Any metal which can be beaten 
out, as with a hammer, or flattened into sheets 
with rollers, is considered malleable. Gold pos- 
sesses this property to the highest degree. It has 
been beaten into leaves one three-hundred-thou- 
sandth of an inch thick. 

Haedness. — This is the resistance which bodies 
offer to being scratched by others. As an exam- 
ple, the diamond has the capacity to scratch all, 
but cannot be scratched by any other. 

Alloys. — Alloys, that is a combination of two or 
more metals, are harder than the pure metals, and 
for this reason jewelry, and coins, are usually 
alloyed. 

The resistance of a body to compression does 
not depend upon its hardness. Strike a diamond 
with a hammer and it flies to pieces, but wood 
does not. One is brittle and the other is tough. 

The machinist can utilize this property by un- 
derstanding that velocity enables a soft material 



82 PEACTICAL MECHANICS FOE BOYS 

to cut a harder one. Thus, a wrought iron disc 
rotating rapidly, will cut such hard substances as 
agate or quartz. 

Eesistaitce. — All metals offer more or less re- 
sistance to the flow of an electric current. Silver 
offers the least resistance, and German silver the 
greatest. Temperature also affects the flow. It 
passes more easily over a cold than a warm con- 
ductor. 

Peksistence. — All metals on receiving heat, will 
retain it for a certain length of time, and will 
finally cool down to the temperature of the sur- 
rounding atmosphere. Some, like aluminum, re- 
tain it for a long time ; others, as iron, will give it 
off quickly. 

Conductivity. — All metals will conduct heat and 
cold, as well as electricity. If one end of a metal 
bar is heated, the heat creeps along to the other 
end until it has the same temperature throughout. 
This is called equalization. 

If a heated bar is placed in contact with another, 
the effect is to increase the temperature of the 
cold bar and lower that of the warm bar. This 
is called reciprocity. 

Molecular Foeces. — Molecular attraction is a 
force which acts in such a way as to bring all 
the particles of a body together. It acts in three 



PEOPEETIES OF MATERIALS 83 

ways, dependent on the particular conditions 
which exist. 

First: Cohesion, This exists between mole- 
cules which are of the same kind, as for instance, 
iron. Cohesion of the particles is very strong in 
solids, much weaker in liquids, and scarcely ex- 
ists at all between the particles in gases. 

Second: Adhesion is that property which ex- 
ists between the surfaces of bodies in contact. 
If two flat surfaces are pressed together, as for 
instance, two perfectly smooth and flat pieces of 
lead, they will adhere. If, for instance, oil should 
be put on the surfaces, before putting them to- 
gether, they would adhere so firmly that it would 
be difficult to pull them apart. 

Third: Affinity. This is another peculiarity 
about materials. Thus, while cohesion binds to- 
gether the molecules of water, it is chemical affin- 
ity which unites two elements, like hydrogen and 
oxygen, of which water is composed. 

PoEosiTY. — All matter has little hollows or 
spaces between the molecules. You know what 
this is in the case of a sponge, or pumice stone. 
Certain metals have the pores so small that it is 
difficult to see them except with a very powerful 
glass. Under great pressure water can be forced 
through the pores of metals, as has been done in 



84 PEACTICAL MECHANICS FOR BOYS 

the case of gold. Water also is porous, but the 
spaces between the molecules are very small. 

Compressibility. — It follows from the foregoing 
statement, that if there are little interstices be- 
tween the molecules, the various bodies can be 
compressed together. This can be done in vary- 
ing degrees with all solids, but liquids, generally, 
have little compressibility. Gases are readily re- 
duced in volume by compression. 

Elasticity. — This is a property by virtue of 
which a body resumes its original form when com- 
pressed. India rubber, ivory and glass are exam- 
ples of elasticity; whereas, lead and clay do not 
possess this property. Air is the most elastic of 
all substances. 

Inertia. — This is a property of matter by virtue 
of which it cannot of itself change its state of 
motion or of rest. 

Newton's first law of motion is, in substance, 
that matter at rest will eternally remain at rest, 
and matter in motion will forever continue in mo- 
tion, unless acted on by some external force. 

A rider is carried over the head of a horse 
when the latter suddenly stops. This illustrates 
the inertia of movement. A stone at rest will al- 
ways remain in that condition unless moved by 
some force. That shows the inertia of rest. 

Momentum. — This is the term to designate the 



PEOPEETIES OF MATEEIALS 85 

quantity of motion in a body. This quantity 
varies and is dependent on the mass, together with 
the velocity. A fly wheel is a good example. It 
continues to move after the impelling force ceases ; 
and a metal wheel has greater momentum than a 
wooden wheel at the same speed, owing to its 
greater mass. 

If, however, the wooden wheel is speeded up 
sufficiently it may have the same momentum as the 
metal one. 

Weight. — All substances have what is called 
weight. This means that everything is attracted 
toward the earth by the force of gravity. Grav- 
ity, however, is different from weight. All sub- 
stances attract each other; not only in the direc- 
tion of the center of the earth, but laterally, as 
well. 

"Weight, therefore, has reference to the pull of 
an object toward the earth; and gravity to that 
influence which all matter has for each other inde- 
pendently of the direction. 

Centkipetal Force. — This attraction of the 
earth, which gives articles the property of weight, 
is termed centripetal force — that is, the drawing 
in of a body. 

Centeifug.il Foece. — The direct opposite of 
centripetal, is centrifugal force, which tends to 



86 PEACTICAL MECHANICS FOR BOYS 

throw outwardly. Dirt flying from a rapidly mov- 
ing wheel illustrates this. 

Capillaey Attraction. — There is a peculiar 
property in liquids, which deserves attention, and 
should be understood, and that is the name given 
to the tendency of liquids to rise in fine tubes. 

It is stated that water will always find its level. 
While this is true, we have an instance where, 
owing to the presence of a solid, made in a peculiar 
form, causes the liquid, within, to rise up far be- 
yond the level of the water. 

This may be illustrated by three tubes of dif- 
ferent internal diameters. The liquid rises up 
higher in the second than in the first, and still 
higher in the third than in the second. The 
smaller the tube the greater the height of the 
liquid. 

This is called capillary attraction, the word 
capillary meaning a hair. The phenomena is best 
observed when seen in tubes which are as fine as 
hairs. The liquid has an affinity for the metal, 
and creeps up the inside, and the distance it will 
thus move depends on the size of the tube. 

The Sap of Trees. — The sap of trees goes up- 
wardly, not because the tree is alive, but due to 
this property in the contact of liquids with a 
solid. It is exactly on the same principle that if 
the end of a piece of blotting paper is immersed 



PEOPEETIES OF MATEEIALS 87 

in water, the latter will creep up and spread over 
the entire surface of the sheet. 

In like manner, oil moves upwardly in a wick, 
and will keep on doing so, until the lighted wick 
is extinguished, when the flow ceases. When it 
is again lighted the oil again flows, as before. 

If it were not for this principle of capillary at- 
traction, it would be difficult to form a bubble of 
air in a spirit level. You can readily see how the 
liquid at each end of the air bubble rounds it off, 
as though it tried to surround it. 

Sound. — Sound is caused by vibration, and it 
would be impossible to convey it without an elas- 
tic medium of some kind. 

Acoustics is a branch of physics which treats of 
sounds. It is distinguished from music which has 
reference to the particular kinds. 

Sounds are distinguished from noises. The lat- 
ter are discordant and abrupt vibrations, whereas 
the former are regular and continuous. 

Sound Mediums. — Gases, vapors, liquids and 
solids transmit vibrations, but liquids and solids 
propagate with greater velocity than gases. 

Vibration. — A vibration is the moving to and 
fro of the molecules in a body, and the greater 
their movement the more intense is the sound. 
The intensity of the sound is affected by the 
density of the atmosphere, and the movement 



88 PEACTICAL MECHANICS FOE BOYS 

of the winds also changes its power of trans- 
mission. 

Sound is also made more intense if a sonorons 
body is near its source. This is taken advantage 
of in musical instruments, where a sounding-board 
is used, as in the case of the piano, and in the 
violin, which has a thin shell as a body for hold- 
ing the strings. 

Another curious thing is shown in the speaking 
tube, where the sound waves are confined, so 
that they are carried along in one line, and as 
they are not interfered with will transmit the 
vibrations to great distances. 

Velocity or Sound. — The temperature of the air 
has also an effect on the rate of transmission, but 
for general purposes a temperature of 62 degrees 
has been taken as the standard. The movement 
is shown to be about 50 miles in 4 minutes, or at 
the rate of 1,120 feet per second. 

In water, however, the speed is four times 
greater; and in iron nearly fifteen times greater. 
Soft earth is a poor conductor, while rock and 
solid earth convey very readily. Placing the ear 
on a railway track will give the vibrations of a 
moving train miles before it can be heard through 
the air. 

Sound Eeflections. — Sound waves move out- 
wardly from the object in the form of wave-like 



PEOPEETIES OF MATEEIALS 89 

rings, but tliose concentric rings, as they are called, 
may be interrupted at various points by obstacles. 
When that is the case the sound is buffeted back, 
producing what is called echoes. 

Resonance. — Materials have a quality that pro- 
duces a very useful result, called resonance, and it 
is one of the things that gives added effect to a 
speaker's voice in a hall, where there is a con- 
stant succession of echoes. A wall distant from 
the speaker about 55 feet, produces an almost in- 
stantaneous reflection of the sound, and at double 
that measurement the effect is still stronger. 
When the distance is too short for the reflecting 
sound to be heard, we have resonance. It enriches 
the sound of the voice, and gives a finer quality to 
musical instruments. 

Echoes. — When sounds are heard after the orig- 
inals are emitted they tend to confusion, and the 
quality of resonance is lost. There are places 
where echoes are repeated ^many times. In the 
chateau of Simonetta, Italy, a sound will be re- 
peated thirty times. 

Speaking Trumpet. — This instrument is an ex- 
ample of the use of reflection. It is merely a bell- 
shaped, or flaring body, the large end of which is 
directed to the audience. The voice talking into 
the small end is directed f orwardly, and is reflected 
from the sides, and its resonance also enables the 



90 PEACTICAL MECHANICS FOE BOYS 

yibrations to carry farther tlian without the use 
of the solid part of the instrument. 

The ear trumpet is an illustration of a sound- 
collecting device, the waves being brought together 
by reflection. 

The Stethoscope. — This is an instrument used 
by physicians, and it is so delicate that the move- 
ments of the organs of the body can be heard with 
great distinctness. It merely collects the vibra- 
tions, and transmits them to the ears by the small 
tubes which are connected with the collecting bell. 

The Vitascope. — Numerous instruments have 
been devised to determine the rate of vibration 
of different materials and structures, the most im- 
portant being the vitascope^ which has a revolvable 
cylinder, blackened with soot, and this being ro- 
tated at a certain speed, the stylus, which is at- 
tached to the vibrating body, in contact with the 
cylinder, will show the number per second, as well 
as the particular character of each oscillation. 

The Phonautogeaph. — This instument is used 
to register the vibration of wind instruments, as 
well as the human voice, and the particular forms 
of the vibrations are traced on a cylinder, the trac- 
ing stylus being attached to a thin vibrating mem- 
brane which is affected by the voice or instrument. 

The Phonogkaph. — This instrument is the out- 
growth of the stylus forms of the apparatus de- 



PEOPEETIES OF MATEEIALS 91 

scribed, but in this case tbe stylus, or needle, is 
fixed to a metallic diaphragm, and its point makes 
an impression on suitable material placed on the 
outside of a revolvable cylinder or disc. 

Light. — Light is the agent which excites the sen- 
sation of vision in the eye. Various theories have 
been advanced by scientists to account for the phe- 
nomenon, and the two most noted views are the 
corpuscular, promulgated by Sir Isaac Newton, 
and the undulatory, enunciated by Huygens and 
Euler. 

The corpuscular theory conceives that light is 
a substance of exceedingly light particles which 
are shot forth with immense velocity. The undu- 
latory theory, now generally accepted, maintains 
that light is carried by vibrations in ether. Ether 
is a subtle elastic medium which fills all space. 

Luminous bodies are those like the sun, which 
emit light. Bays may diverge, that is, spread out ; 
converge, or point toward each other ; or they may 
be parallel with each other. 

Velocity of Light. — Light moves at the rate 
of about 186,000 miles a second. As the sun is 
about 94,000,000 miles from the earth, it takes 8^ 
minutes for the light of the sun to reach us. 

Eeflection. — One of the most important things 
connected with light is that of reflection. It is 
that quality which is utilized in telescopes, micro- 

40 



92 PEACTICAL MECHANICS FOE BOYS 

scopes, mirrors, heliograpli signaling and other 
like apparatus and uses. Tlie underlying princi- 
ple is, that a ray is reflected, or thrown back from 
a mirror at the same angle as that which produces 
the light. 

When the rays of the sun, which are, of course, 
parallel, strike a concave mirror, the reflecting 
rays are converged; and when the rays strike a 
convex mirror they diverge. In this way the prin- 
ciple is employed in reflecting telescopes. 

Eefractioit. — This is the peculiar action of light 
in passing through substances. If a ray passes 
through water at an angle to the surface the ray 
will bend downwardly in passing through, and 
then again pass on in a straight line. This will 
be noticed if a pencil is stood in a glass of water 
at an angle, when it will appear bent. 

Eefraction is that which enables light to be di- 
vided up, or analyzed. In this way white light 
from the sun is shown to be composed of seven 
principal colors. 

Colors. — If the light is passed through a prism, 
which is a triangularly shaped piece of glass, the 
rays on emerging will diverge from each other, 
and when they fall on a wall or screen the colors 
red, orange, yellow, green, blue, indigo and violet 
are shown. 



PROPEETIES OF MATEEIALS 93 

The reason for this is that the ray in passing 
through the prism has the ditferent colors in it 
refract at different angles, the violet bending more 
than the red. 

The Spectroscope. — The ability to make what 
is thus called a spectrum , brought forth one of 
the most wonderful instruments ever devised by 
man. If any metal, or material, is fused, or put 
in such a condition that a ray of light can be ob- 
tained from it, and this light is passed through a 
prism, it will be found that each substance has 
its owTi peculiar divisions and arrangements of 
colors. 

In this way substances are determined by what 
is called spectrum analysis, and it is by means of 
this instrument that the composition of the sun, 
and the planets and fixed stars are determined. 

The Eaixbow. — The rainbow is one of the effects 
of refraction, as the light, striking the little globu- 
lar particles of water suspended in the air, pro- 
duces a breaking up of the white light into its 
component colors, and the sky serves as a back- 
ground for viewing the analysis thus made. 

Heat. — It is now conclusively proven, that heat, 
like light, magnetism and electricity, is merely a 
mode of motion. 

The mechanical theory of heat may be shown 
by rubbing together several bodies. Heat expands 



94 PEACTICAL MECHANICS' FOR BOYS 

all substances, except ice, and in expanding devel- 
ops an enormous force. 

Expansion. — In like manner liquids expand with, 
heat. The power of mercury in expanding may 
be understood when it is stated that a pressure 
of 10,000 pounds would be required to prevent the 
expansion of mercury, when heated simply 10 de- 
grees. 

Gases also expand. While water, and the dif- 
ferent solids, all have their particular units of 
expansion, it is not so with gases, as all have the 
same coefficient. 



CHAPTER VIII 

HOW DEAUGHTING BECOMES A VALUABLE AID 

The ability to read drawings is a necessary part 
of the boy's education. To know how to use the 
tools, is still more important. In conveying an idea 
about a piece of mechanism, a sketch is given. Now, 
the sketch may be readable in itself, requiring no 




Plain Circle 

explanation, or it may be of such a nature that it 
will necessitate some written description. 

Lines in Dkawing. — ^In drawing, lines have a 
definite meaning. A plain circular line, like Fig. 
95, when drawn in that way, conveys three mean- 
igs : It may represent a rim, or a bent piece of wire ; 
it may illustrate a disk ; or, it may convey the idea 
of a ball. 

Suppose we develop them to express the three 
forms accurately. Fig. 96, by merely adding an 

95 



96 PEACTICAL MECHANICS FOR BOYS 

interior line, shows that it is a rim. There can be 
no further donbt about that expression. 

Fig. 97 shows a single line, but it will now be 
noticed that the line is thickened at the lower right- 
hand side, and from this you can readily infer 
that it is a disk. 

Shading. — Fig. 98, by having a few shaded lines 
on the right and lower side, makes it have the ap- 
pearance of a globe or a convex surface. 




JFligde.^ 7^iq,9Z T^i^.Qe. 

Ring Raised Surface Sphere 

Shading or thickening the lines also gives an- 
other expression to the same circular line. 

In Fig. 99, if the upper and left-hand side of the 
circle is heavily shaded, it shows that the area with- 
in the circle is depressed, instead of being raised. 

DiKECTioN OF Shade. — On the other hand, if the 
shading lines, as in Fig. 100, are at the upper left- 
hand side, then the mind at once grasps the idea 
of a concave surface. 

The first thing, therefore, to keep in mind, is this 



DEAUGHTING VALUABLE AID 



97 



fact: That in all mechamcal drawing, the light is 
supposed to shine down from the upper left-hand 
corner and that, as a result, the lower vertical line, 
as well as the extreme right-hand vertical line, 
casts the shadows, and should, therefore, be made 
heavier than the upper horizontal, and the left- 
hand vertical lines. 

There are exceptions to this rule, which will be 




Depressed Surface 



Concave 



readily understood by following out the illustra- 
tions in the order given below. 

Pekspectives. — The utility of the heavy lines 
will be more apparent when drawing square, rec- 
tangular, or triangular objects. 

Let us take Fig. 101, which appears to be the 
perspective of a cube. Notice that all lines are of 
the same thickness. "When the sketch was first 
brought to me I thought it was a cube ; but the ex- 
planation which followed, showed that the man who 



98 PEACTICAL MECHANICS FOE BOYS 



made the sketch had an entirely different mean- 
ing. 

He had intended to convey to my mind the idea 
of three pieces, A, B, C, of metal, of equal size^ 
joined together so as to form a triangularly shaped 




l^ig-IOl 






Forms of Cvhical Ovilines 

pocket as shown in Fig. 101. The addition of the 
inner lines, like D, quickly dispelled the sugges- 
tion of the cube. 

" But," he remarked, " I want to use the thinnest 
metal, hke sheets of tin ; and you show them thick 
Iby adding the inner lines." 

Such being the case, if we did not want to show 



DEAUGHTING VALUABLE AID 99 



tliickness as its structural form, we had to do it by 
making the lines themselves and the shading give 
that structural idea. This was done by using the 
single lines, as in Fig. 103, and by a slight shading 
of the pieces A, B, C. 





2^ig.i06. 



Shading Edges * 

The Most Pkoistounced Lines. — If it had been 
a cube, or a solid block, the corners nearest the eye 
ivould have been most pronounced, as in Fig. 104, 
and the side next to the observer would have been 
darkest. 

This question of light and shadow is what ex- 
presses the surface formation of every drawing. 
Simple strokes form outlines of the object, but their 
thickness, and the shading, show the character en- 
closed by the lines. 



100 PEACTICAL MECHANICS FOE BOYS 



DiEECTioN OF Light. — Now, as stated, the east- 
ing of the shadow downward from the upper left- 
hand corner makes the last line over which it passes 
the thickest, and in Figs. 105 and 106 they are not 
the extreme lines at the bottom and at the right 
side, because of the close parallel lines. 

In Figs. 109 and 110 the blades superposed on 
the other are very thin, and the result is the lines 



[ 



J [ 



2^iff- 707. 2^J0d. 

Illustrating Heavy Lines 

at the right side and bottom are made much heavier. 

This is more fully shown in Figs. 107 and 108. 
Notice the marked difference between the two fig- 
ures, both of which show the same set of pulleys, 
and the last figure, by merely having the lower 
and the right-hand lines of each pulley heavy, 
changes the character of the representation, and 
tells much more clearly what the draughtsman 
sought to convey. 

Scale Drawings. — All drawings are made to a 



DEAUGHTING VALUABLE AID 101 



scale where the article is large and cannot be in- 
dicated the exact size, using parts of an inch to 
represent inches ; and parts of a foot to represent 
feet. 

In order to reduce a drawing where a foot is the 
nnit, it is always best to nse one-and-a-half inches, 
or twelve-eighths of an inch, as the basis. In this 



T^tg, 709. 



T^igJ/O. 



Lines on Plain Surfaces 

way each eighth of an inch represents an inch. 
If the drawing should be made larger, then use 
three inches, and in that way each inch would be 
one-quarter of an inch. 

The drawing should then have marked, in some 
conspicuous place, the scale, like the following: 
" Scale, IVo'' = 1"^ or, " Scale 3'' = V ." 

Degree, and What it Means. — A degree is not 



102 PEACTICAL MECHANICS FOE BOYS 

a measurement. The word is used to designate an 
interval, a position, or an angle. Every circle has 
360 degrees, and when a certain degree is men- 
tioned, it means a certain angle from what is called 
a base line. 




Illustrating Degrees 

Look at Fig. 111. This has a vertical line A, and 
a horizontal line B. The circle is thus divided into 
four parts, and where these lines A, B, cross the 
circle are the cardinal points. Each of the four 
parts is called a quadrant, and each quadrant has 
90 degrees. 

Any line, like C, which is halfway between A 
and B, is 45 degrees. Halfway between A and C, 



DEAUGHTING VALUABLE AID 103 

or between B and C, like the line J), is 22>4 de- 
grees. 

Memokizing Angles. — It is well to try and re- 
member these lines by fixing the angles in the mem- 
ory. A good plan is to divide any of the quad- 
rants into thirds, as shown by the points E, F, and 
then remember that E is 30 degrees from the hori- 




Section Lining 

zontal line B, and that F is 60 degrees. Or, you 
might say that F is 30 degrees from the vertical 
line A, and E 60 degrees from A. Either would 
be correct. 

Section Lining. — ^In representing many parts of 
a machine, or article, it is necessary to show the 
parts cut off, which must be illustrated by what is 
called "section lining." Adjacent parts should 



104 PEACTICAL MECHANICS FOE BOYS( 

have the section lines running at right angles to 
each other, and always at 45 degrees. 

Look at the ontside and then the inside views of 
Fig. 112, and you will see how the contiguous parts 
have the angles at right angles, and clearly illus- 




Drawing an Ellipse 

trate how every part of the wrench is made. Skill 
in depicting an article, for the purpose of construct- 
ing it from the drawing, will make the actual work 
on the bench and lathe an easy one. 

Making Ellipses and Iekegulae Curves. — This 
is the hardest thing to do with drawing tools. A 
properly constructed elliptical figure is difficult, 



DEAUGHTING VALUABLE AID 105 

principally, because two different sized curves are 
required, and the pen runs from one curve into the 
other. If the two curves meet at the wrong place, 
you may be sure you will have a distorted ellipse. 

Follow the directions given in connection with 
Fig. 113, and it will give you a good idea of merg- 
ing the two lines. 

First. Draw a horizontal line. A, which is in the 
direction of the major axis of the ellipse — that is, 
the longest distance across. The narrow part of 
the ellipse is called the minor axis. 

Second. Draw a perpendicular line, B, which 
we will call the center of the ellipse, where it 
crosses the line A. This point must not be con- 
founded with the focus. In a circle the focus is the 
exact center of the ring, but there is no such thing 
in an ellipse. Instead, there are two focal points, 
called the foci, as you will see presently. 

Third. Step off two points or marking places, 
as we shall term them, equidistant from the line B, 
and marked C, C. These marks will then represent 
the diameter of the ellipse across its major axis. 

Fourth. We must now get the diameter of the 
minor axis, along the line B. This distance will 
depend on the perspective you have of the figure. 
If you look at a disk at an angle of about 30 de- 
grees it will be half of the distance across the ma- 
jor axis. 




106 PEACTICAL MECHANICS FOE BOYS 

So yon may understand this examine Fig. 114. 
The first sketch shows the eye looking directly at 
the disk 1. In the second sketch the disk is at 30 
degrees, and now the lines 2 2, from the eye, indi- 
cate that it is just half the width that it was when 
the lines 3 3 were projected. The marks D D, 
therefore, indicate the distance across the minor 
axis in Fig. 113. 

60'* 
no 

Perspedion in Angles 

Fifth. We must now find the focal points of 
the ellipse. If the line A on each side of the cross 
line B is divided into four parts, the outer marks 
E may he used for the foci, and will he the places 
where the point of the compass, or bow pen, is to 
he placed. 

Sixth. Describe a circle F, so it passes through 
the mark C, and move the point of the compass 
to the center of the ellipse, at the star, and describe 
a circle line G, from the mark C to the line B. This 
will give a centering point H. Then draw a line 
I from H to E, and extend it through the circle F, 

Seventh. If the point of the compass is now put 



DEAUGHTING VALUABLE AID 107 

at H, and the pencil or pen on the circle line F, the 
curve J can be drawn, so the latter curve and the 
curve F will thus merge perfectly at the line I. 

The Focal Points. — The focal points can he 
selected at any arbitrary point, between C and the 
line B, and the point H may be moved closer to or 
farther away from the line A, and you will succeed 
in making the ellipse correct, if you observe one 




Perspectives of Cubes 



'jTigJ/r. 



thing, namely: The line I, which must always run 
from H to E, and intersects the circle F, is the start- 
ing or the ending point for the small curve F or the 
large circle J. 

IsoMETKic AND PERSPECTIVE. — A figuro may be 
drawn so as to show an isometric or a perspective 
view. Thus, a cube can be drawn so as to make an 
isometric figure, as in Fig. 115, where the three 
sides are equal to each other. 

Isometric means a method of drawing any object 
in such a manner that the height, length and 

41 



108 PEACTICAL MECHANICS FOE BOYS 

breadth may be shown in the proportion they really 
bear to each other. Fig. 115 has the sides not only 
equal to each other, in appearance to the eye, but 
they have the same outlines and angles. 

Contrast this figure with Figs. 116 and 117. In 
Fig. 116 two of the sides are equal in angles and 




~7^^J/6. Fl'otractor . 

Section Lining Metals 

outline ; and in Fig. 117 each side has a different 
outline, and different angles. Nevertheless, all the 
cubes are, in reality, of the same dimension. 

The Peotkactoe. — This is a most useful tool for 
the draughtsman. It enables the user to readily 
find any angle. Fig. 118 shows an approved form 
of the tool for this purpose. 

Suggestions in Deawing. — ^As in the use of all 



DEAUGHTING VALUABLE AID 109 

other tools, so with, the drawing instrument, it must 
be kept in proper order. If the points are too fine 
they mil cut the paper ; if too blunt the lines will 
be ragged. In whetting the points hold the pen at 
an angle of 12 degrees. Don't make too long an 
angle or slope, and every time you sharpen hold 




2^i^. 1i9. ir^tTtg fJm Trotractor , 



it at the same angle, so that it is ground back, and 
not at the point only. 

Holding the Pen. — The drawing pen should be 
held as nearly vertical as possible. Use the clean- 
ing rag frequently. If the ink does not flow freely, 
after you have made a few strokes, as is frequently 
the case, gently press together the points. The 
least grit between the tines will cause an irregular 
flow. 



110 PEACTICAL MECHANICS FOR BOYS 

Inks. — As prepared liquid inks are now univer- 
sally used, a few suggestions might be well con- 
cerning them. After half the bottle has been used, 
add a half teaspoonful of water, shake it well, and 
then strain it through a fine cotton cloth. This will 
remove all grit and lint that is sure to get into the 
l)ottle however carefully it may be corked. 





^teel 



C(/kitp.lltetaU 








Bra6&. 






Section Lining Metals 

Teacing CLOTif. — It is preferable to use the dull 
side of the tracing cloth for the reasons that, as the 
<?loth is rolled with the glossy side inside, the figure 
w^hen drawn on the other side will be uppermost, 
and will thus lie flat ; and on the other hand, the 
ink will take better on the dull side. 

If the ink does not flow freely, use chalk, ^e 
pumice stone, or talc, and rub it in well with a clean 
doth, and then wipe off well before beginning to 
trace. 



DRAUGHTING VALUABLE AID 111 

Detail Papee. — The detail paper, on which the 
drawing is first made in pencil, should show the fig- 
ure accurately, particularly the points where the 
bow pen are to be used, as well as the measurement 
points for the straight lines. 

How TO Proceed. — Make the circles, curves, and 
irregular lines first, and then follow with the 
straight lines. Where the point of the circle pen 
must be used for a large number of lines, as, for 
instance, in shading, the smallest circles should be 
made first, and the largest circles last, because at 
every turn the centering hole becomes larger, and 
there is liability to make the circles more or less 
irregular. Such irregularity will not be so notice- 
able in the large curves as in the smaller ones. 

Indicating Material by the Section Lines. — 
In section lining different materials can be indi- 
cated by the character of the lines, shown in Fig. 
120. 



CHAPTER IX 

TEEATMENT AND USE OF METALS 

Annealin^g. — A very important part of the nov- 
ice's education is a knowledge pertaining to tlie 
annealing of metals. Unlike the artisan in wood, 
who works the materials as he finds them, the ma- 
chinist can, and, in fact, with many of the sub- 
stances, must prepare them so they can be handled 
or cut by the tools. 

Annealing is one of the steps necessary with all 
cutting tools, and it is an absolute requirement with 
many metals for ordinary use, as well as for many 
other articles like glass. This is particularly true 
in the use of copper. 

Toughness and Eiasticity. — It means the put- 
ting of metals in such a condition that they will not 
only be less brittle, but also tougher and more elas- 
tic. Many substances, like glass, must be annealed 
before they can be put in condition for use, as this 
material when first turned out is so brittle that the 
slightest touch will shatter it, so that it must be 
toughened. 

Malleable or wrought iron, if subjected to pres- 
sure, becomes brittle, and it is necessary to anneal 
it. Otherwise, if used, for instance, for boiler 

112 



TEEATMENT OF MATEEIALS 113 

plates, from the rolled sheets, it would stand but 
little pressure. 

The most immediate use the boy will have is the 
treatment of steel. He must learn the necessity of 
this process, and that of tempering, in all his cut- 
ting tools, and in the making of machinery where 
some parts are required to be constructed of very 
hard metal. 

The Process. — To anneal steel it must be heated 
to a bright cherry red and then gradually cooled 
down. For this purpose a bed of fine charcoal^ or 
iron filings and lime, is prepared, in which the ar- 
ticle is embedded, and permitted to remain until 
it is cold. 

There are many ways of doing the work, partic- 
ularly ii Jie use of substances which will the most 
readily give up their carbon to the tool. Yellow 
prussiate of potash is an excellent medium, and this 
is sprinkled over the cherry-heated article to be an- 
nealed. The process may be repeated several times. 

Tempeeing. — This is the reverse of annealing as 
understood in the art. The word itself does not 
mean to " harden," but to put into some intermedi- 
ate state. For instance, " tempered clay " means 
a clay which has been softened so it can be readily 
worked. 

On the other hand, a tempered steel tool is put 
into a condition w^here it is hardened, but this hard- 



114 PEACTICAL MECHANICS' FOR BOYS 

ness is also accompanied by another quality, name- 
ly, toughness. For this reason, the word temper, 
and not hardness, is referred to. A lathe tool, if 
merely hardened, would be useless for that purpose. 

Tempering Contrasted with Annealing. — It 
will be observed that in annealing three things are 
necessary : First, heating to a certain temperature ; 
second, cooling slowly; third, the particular man- 
ner of cooling it. 

In tempering, on the other hand, three things are 
also necessary: 

First : The heating temperature should be a dull 
red, which is less than the annealing heat. 

Second: Instead of cooling slowly the article 
tempered is dipped into a liquid which suddenly 
chills it. 

Third : The materials used vary, but if the arti- 
ticle is plunged into an unguent made of mercury 
and bacon fat, it will impart a high degree of 
toughness and elasticity. 

Materials Used. — Various oils, fats and rosins 
are also used, and some acids in water are also 
valuable for this purpose. Care should be taken to 
have sufficient amount of liquid in the bath so as 
not to evaporate it or heat it up too much when it 
receives the heated body. 

Different parts of certain articles require vary- 
ing degrees of hardness, like the tangs of files. The 



TEEATMENT OF MATERIALS 115 

cutting body of the file must be extremely hard, and 
rather brittle than tough. If the tang should be of 
the same hardness it would readily break. 

Gradual Tempering. — To prevent this, some 
substance like soap suds may be used to cool down 
the tang, so that toughness without hardness is 
imparted. 

The tempering, or hardening, like the annealing 
process, may be repeated several times in succes- 
sion, and at each successive heating the article is 
put at a higher temperature. 

If any part of a body, as, for instance, a hammer- 
head, should require hardening, it may be plunged 
into the liquid for a short distance only, and this 
will harden the pole or peon while leaving the other 
part of the head soft, or annealed. 

Glycerine is a good tempering substance, and to 
this may be added a small amount of sulphate of 
potash. 

Fluxing. — The word flux means to fuse or to 
melt, or to put into a liquid state. The office of a 
flux is to facilitate the fusion of metals. But fluxes 
do two things. They not only aid the conversion 
of the metal into a fluid state, but also serve as a 
means for facilitating the unity of several metals 
which make up the alloy, and aid in uniting the 
parts of metals to be joined in the welding of 
parts. 



116 PEACTICAL MECHANICS FOR BOYS 

Uniting Metals. — Metals are united in three 
ways, where heat is used : 

First : By heating two or more of them to such 
a high temperature that they melt and form a com- 
pound, or an alloy, as it is called. 

Second : By heating up the points to be joined, 
and then lapping the pieces and hammering the 
parts. This is called forge work or welding. 

Third : By not heating the adjacent parts and 
using an easily fusible metal, which is heated up 
and run between the two, by means of a soldering 
iron. 

The foreign material used in the first is called a 
flux; in the second it is termed a welding com- 
pound ; and in the third it is known as a soldering 
acid, or soldering fluid. 

The boy is not so much interested in the first 
process, from the standpoint of actual work, but 
it is necessary that he should have some understand- 
ing of it. 

It may be said, as to fluxes, generally, that they 
are intended to promote the fusion of the liquefy- 
ing metals, and the elements used are the alkalis, 
such as borax, tartar, limestone, or fluor spar. 

These substances act as reducing or oxidizing 
agents. The most important are carbonate of soda, 
potash, and cyanide of potassium. Limestone is 
used as the flux in iron-smelting. 



TEEATMENT OF MATERIALS 117 

Welding Compounds. — Elsewhere formulas are 
given of the compounds most desirable to use. It 
is obvious that the application of these substances 
on the heated surfaces, is not only to facilitate the 
heating, but to prepare the articles in such a man- 
ner that they will more readily adhere to each other. 

Oxidation. — Oxidation is the thing to guard 
against in welding. The moment a piece of metal, 
heated to whiteness, is exposed, the air coats it with 
a film which is called an oxide. To remove this the 
welding compound is applied. 

The next office of the substance thus applied, is 
to serve as a medium for keeping the welding parts 
in a liquid condition as long as possible, and thus 
facilitate the unity of the joined elements. 

When the hammer beats the heated metals an ad- 
ditional increment of heat is imparted to the weld, 
due to the forcing together of the molecules of the 
iron, so that these two agencies, namely, the com- 
pound and the mechanical friction, act together to 
unite the particles of the metal. 

Soldering. — Here another principle is involved, 
namely, the use of an intermediate material be- 
tween two parts which are to be united. The 
surfaces to be brought together must be thor- 
oughly cleaned, using such agents as will prevent 
the formation of oxides. 

The parts to be united may be of the same, or of 



118 PEACTICAL MECHANICS FOE BOYS 

different materials, and it is in this particular that 
the workman must be able to make a choice of 
the solder most available, and whether hard or 
soft. 

Soft Soldee. — A soft solder is usually employed 
where lead, tin, or alloys of lead, tin and bismuth 
are to be soldered. These solders are all fusible 
at a low temperature, and they do not, as a result, 
have great strength. 

Bismuth is a metal which lowers the fusing point 
of any alloy of which it forms a part, while lead 
makes the solder less fusible. 

Haed Soldee. — These are so distinguished be- 
cause they require a temperature above the low red 
to fuse them. The metals which are alloyed for 
this purpose are copper, silver, brass, zinc and tin. 
Various alloys are thus made which require a high 
temperature to flux properly, and these are the 
ones to use in joining steel to steel, the parts to be 
united requiring an intense furnace heat. 

Speltee.— The alloy used for this purpose is 
termed "spelter," and brass, zinc and tin are its 
usual components. The hard solders are used for 
uniting brass, bronze, copper, and iron. 

Whether soft or hard solder is used, it is obvious 
that it must melt at a lower temperature than the 
parts which are to be joined together. 

There is one peculiarity with respect to alloys: 



TEEATMENT OF MATERIALS 119 

They melt at a lower temperature than either of 
the metals forming the alloys. 

SoLDEKiNG Acid. — Before beginning the work of 
soldering, the parts must be cleaned by filing or 
sandpapering, and coated with an acid which neu- 
tralizes the oxygen of the air. 

This is usually muriatic acid, of which use, say, 
one quart and into this drop small pieces of zinc. 
This will effervesce during the time the acid is dis- 
solving the zinc. When the boiling motion ceases, 
the liquid may be strained, or the dark pieces re- 
moved. 

The next step is to dissolve two ounces of sal 
ammoniac in a third of a pint of water, and in an- 
other vessel dissolve an ounce of chloride of tin. 

Then mix the three solutions, and this can be 
placed in a bottle, or earthen jar or vessel, and it 
will keep indefinitely. 

The Soldeking Ieon. — A large iron is always 
better than a small one, particularly for the reason 
that it will retain its heat better. This should al- 
ways be kept tinned, which can be done by, heating 
and plunging it into the soldering solution, and the 
solder will then adhere to the iron and cover the 
point, so that when the actual soldering takes place 
the solder will not creep away from the tool. 

By a little care and attention to these details, the 
work of uniting metals will be a pleasure. It is so 



120 PRACTICAL MECHANICS FOE BOYS 

« 

often the ease, however, that the apparatus for do- 
ing this work is neglected in a shop; the acid is 
allowed to become dirty and full or foreign matter, 
and the different parts separated. 



•4^ 



CHAPTEE X 

ON GEAEING AND HOW OKDEKED 

The teclmical name for gears, the manner of 
measuring them, their pitch and like terms, are 
most confusing to the novice. As an aid to the 
understanding on this subject, the wheels are illus- 
trated, showing the application of these terms. 

Spue and Pinion. — When a gear is ordered a 
specification is necessary. The manufacturer will 
know what you mean if you use the proper terms, 
and you should learn the distinctions between spur 
and pinion, and why a bevel differs from a miter 
gear. 

If the gears on two parallel shafts mesh with 
each other, they both may be of the same diameter, 
or one may be larger than the other. In the latter 
case, the small one is the pinion, and the larger 
one the spur wheel. 

Some manufacturers use the word "gear" for 
"pinion," so that, in ordering, they call them gear 
and pinion, in speaking of the large and small 
wheels. 

Measueing a Geae. — The first thing to specify 
would be the diameter. Now a spur gear, as well 
as a pinion, has three diameters; one measure 

121 



122 PEACTICAL MECHANICS FOR BOYS 

across the outer extremities of the teeth ; one meas- 
ure across the wheel from the base of the teeth; 
and the distance across the wheel at a point mid- 
way between the base and end of the teeth. 

These three measurements are called, respec- 
tively, "outside diameter," "inside diameter," and 




ie 



le- 



2rcg.m. 



- In d ideDiamefer - 
- Fitch Utavnede? '— 
OlL&6taeJi6ame(er • 



^"pur Gears 



"pitch diameter." When the word diameter is 
used, as applied to a gear wheel, it is always under- 
stood to mean the "pitch diameter." 

Pitch. — This term is the most difficult to under- 
stand. When two gears of equal size mesh to- 
gether, the pitch line, or the pitch circle, as it is 



ON GEAEING AND HOW OEDERED 12S 



also called, is exactly midway between the centers 
of the two wheels. 

Now the number of teeth in a gear is calculated 
on the pitch line, and this is called : 



f^ — S^ — ^ 




Fig, 12%, Miter Gear Pitch 

Diametral Pitch. — To illustrate: If a gear 
has 40 teeth, and the pitch diameter of the wheel 
is 4 inches, there are 10 teeth to each inch of the 
pitch diameter, and the gear is then 10 diametral 
pitch. 

CiECULAR Pitch. — Now the term "circular pitch" 
grows out of the necessity of getting the measure- 
ment of the distance from the center of one tooth 



124 PEACTICAL MECHANICS FOR BOYS 

to the center of the next, and it is measured along 
the pitch line. 

Supposing you wanted to know the number of 
teeth in a gear where the pitch diameter and the 
diametral pitch are given. You would proceed as 
follows : Let the diameter of the pitch circle be 




■IargpAirPitf.h Dmm. 



rAC£ 



2^ig. tlSa, JBeifel Gea?'^ . 




10 inches, and the diameter of the diametral pitch 
be 4 inches. Multiplying these together the prod- 
uct is 40, thus giving the number of teeth. 

It will thus be seen that if you have an idea of 
the diametral pitch and circular pitch, you can 
pretty fairly judge of the size that the teeth will 
be, and thus enable you to determine about what 
kind of teeth you should order. 



ON GEAEING^ AND HOW OEDERED 125 

How TO Order a Geae. — In proceeding to order, 
therefore, you may give the pitch, or the diameter 
of the pitch circle, in which latter case the manu- 
facturer of the gear will understand how to deter- 
mine the number of the teeth. In case the inter- 
meshing gears are of different diameters, state the 




T^ig.f^. MiMr Gear6 . 



number of teeth in the gear and also in the pinion, 
or indicate what the relative speed shall be. 

This should be followed by the diameter of the 
hole in the gear and also in the pinion ; the backing 
of both gear and pinion; the width of the face; 
the diameter of the gear hub; diameter of the 
pinion hub ; and, finally, whether the gears are to 
be fastened to the shafts by key-ways or set- 
screws. 

Fig. 122 shows a sample pair of miter gears, 



126 PEACTICAL MECHANICS FOE BOYS 

mth the measurements to indicate how to make 
the drawings. Fig. 123 shows the bevel gears. 

Bevel and Mitee Geaks. — When two intermesh- 
ing gears are on shafts which are at right angles 
to each other, they may be eqnal diametrically, or 
of different sizes. If both are of the same diame- 



JPilch cF CJmin 




.' SPttch line 



Z^i^./Ba-^moQi^^^^ 



ter, they are called bevel gears; if of different 
diameters, miter gears. 

It is, in ordering gears of this character, that 
the novice finds it most difficult to know just what 
to do. In this case it is necessary to get the 
proper relation of speed between the two gears, 
and, for convenience, we shall, in the drawing, 
make the gears in the relation of 2 to 1. 

Drawing Gears. — Draw two lines at right angles, 



ON GEAEING AND HOW OEDEEED 127 

Fig. 124, as 1 and 2, marking off the sizes of 
the two wheels at the points 3, 4. Then draw a 
vertical line (A) midway between the marks of the 
line 2, and this will be the center of the main pinion. 

Also draw a horizontal line (B) midway between 
the marks on the vertical line (1), and this will 
represent the center of the small gear. These two 
cross lines (A, B) constitute the intersecting axes 
of the two wheels, and a line (5), drawn from the 
mark (3 to 4), and another line (6), from the axes 
to the intersecting points of the lines (1, 2), will 
give the pitch line angles of the two wheels. 

Spkocket Wheels. — For sprocket wheels the 
pitch line passes centrally through the rollers (A) 
of the chain, as shown in Fig. 125, and the pitch 
of the chain is that distance between the centers 
of two adjacent rollers. In this case the cut of 
the teeth is determined by the chain. 



CHAPTER XI 

MECHANICAL POWEES 

The Levee. — The lever is the most wonderful 
mechanical element in the world. The expression, 
lever, is not employed in the sense of a stick or a 
bar which is used against a fulcrum to lift or push 
something with, but as the type of numerous de- 
vices which employ the same principle. 

Some of these devices are, the wedge, the screw, 
the pulley and the inclined plane. In some form 
or other, one or more of these are used in every 
piece of mechanism in the world. 

Because the lever enables the user to raise or 
move an object hundreds of times heavier than is 
possible without it, has led thousands of people 
to misunderstand its meaning, because it has the 
appearance, to the ignorant, of being able to manu- 
facture power. 

Weong Infeeences feom Use of Levee. — This 
lack of knowledge of first principles, has bred and 
is now breeding, so-called perpetual motion in- 
ventors (?) all over the civilized world. It is 
surprising how many men, to say nothing of boys, 
actually believe that power can be made without 
the expenditure of something which equalizes it. 

128 



MECHANICAL POWEES 129 

The boy should not be led astray in this par- 
ticular, and I shall try to make the matter plain 
by using the simple lever to illustrate the fact that 
whenever power is exerted some form of energy 
is expended. 

In Fig. 126 is a lever (A), resting on a fulcrum 
(B), the fulcrum being so placed that the lever is 
four times longer on one side than on the other. 
A weight (C) of 4 pounds is placed on the short 




"^ 7^1^. 1R6. 

Simple Lever 

end, and a 1-pound weight (D), called the power, 
on the short end. It will thus be seen that the 
lever is balanced by the two weights, or that the 
weight and the power are equal. 

The Lever Principle. — Now, without stopping 
to inquire, the boy will say : "Certainly, I can un- 
derstand that. As the lever is four times longer 
on one side of the fulcrum than on the other side, 
it requires only one-fourth of the weight to bal- 
ance the four pounds. But suppose I push down 
the lever, at the point where the weight (D) is. 



130 PEACTICAL MECHANICS FOE BOYS 

then, for every pound I push down I can raise 
four pounds at C. In that case do I not produce 
four times the power I" 

I answer, yes. But while I produce that power 
I am losing something which is equal to the power 
gained. What is that? 

First : Look at Fig. 127 ; the distance traveled. 
The long end of the lever is at its highest point, 
which is A; and the short end of the lever is at 



Lever Action 

its lowest point C. When the long end of the 
lever is pushed down, so it is at B, it moves four 
times farther than the short end moves upwardly, 
as the distance from C to D is just one-fourth 
that from A to B. The energy expended in mov- 
ing four times the distance balances the power 
gained. 

PowEK vs. Distance Teaveled. — From this the 
following law is deduced: That whatever is 
gained in power is lost in the distance traveled. 



MECHANICAL POWEES 131 

Second: Using the same figure, supposing it 
was necessary to raise the short end of the lever, 
from C to D, in one second of time. In that case 
the hand pressing down the long end of the lever, 
would go from A to B in one second of time ; or it 
would go four times as far as the short end, in 
the same time. 

Power vs. Loss in Time. — This means another 
law: That what is gained in power is lost in 
time. 

Distinguish clearly between these two motions. 
In the first case the long end of the lever is moved 
down from A to B in four seconds, and it had to 
travel four times the distance that the short end 
moves in going from C to D. 

In the second case the long end is moved down, 
from A to B, in one second of time, and it had to 
go that distance in one-fourth of the time, so that 
four times as much energy was expended in the 
same time to raise the short end from C to D. 

Wrongly Directed Energy. — More men have 
gone astray on the simple question of the power 
of the lever than on any other subject in mechan. 
ics. The writer has known instances where men 
knew the principles involved in the lever, who 
would still insist on trying to work out mechanical 
devices in which pulleys and gearing were in- 
volved, without seeming to understand that those 



132 PEACTICAL MECHANICS FOR BOYS 

mechanical devices are absolutely the same in 
principle. 

This will be made plain by a few illustrations. 
In Fig. 128, A is a pulley four times larger, diamet- 
rically, than B, and C is the pivot on which they 
turn. The pulleys are, of course, secured to each 
other. In this case we have the two weights, one 




The Pulley 

of four pounds on the belt, which is on the small 
pulley (B), and a one-pound weight on the belt 
from the large pulley (A). 

The LE^rER and the Puli^ey. — If we should sub- 
stitute a lever (D) for the pulleys, the similarity 
to the lever (Fig. 127) would be apparent at once. 
The pivot (C) in this case would act the same as 
the pivot (C) in the lever illustration. 

In the same manner, and for like reasons, the 




MECHANICAL POWEES 133 

wedge, tlie screw and the incline plane, are differ- 
ent structural applications of the principles set 
forth in the lever. 

Whenever two gears are connected together, the 
lever principle is used, whether they are the same 
in size, diametrically, or not. If they are the 
same size then no change in power results; but 
instead, thereof, a change takes place in the direc- 
tion of the motion. 

■'OS 

Change of Direction 

When one end of the lever (A) goes down, the 
other end goes up, as shown in Fig. 129 ; and in 
Fig. 130, when the shaft (C) of one wheel turns 
in one direction, the shaft of the other wheel turns 
in the opposite direction. 

It is plain that a gear, like a lever, may change 
direction as well as increase or decrease power. 
It is the thorough knowledge of these facts, and 
their application, which enables man to make the 
wonderful machinery we see on every hand. 

SouKCEs OF PowEK. — Power is derived from a 



134 PEACTICAL MECHANICS FOR BOYS 

variety of sources, but wliat are called the prime 
movers are derived from heat, through the various 
fuels, from water, from the winds and from the 
tides and waves of the ocean. In the case of water 
the power depends on the head, or height, of the 
surface of the water above the discharging orifice. 

Water Power. — A column of water an inch 
square and 28 inches high gives a pressure at the 
base of one pound ; and the pressure at the lower 
end is equal in all directions. If a tank of water 
28 inches high has a single orifice in its bottom 
1'' X 1" in size, the pressure of water through that 
opening will be only one pound, and it will be one 
pound through every other orifice in the bottom of 
the same size. 

Calculating Fuel Energy. — Power from fuels 
depends upon the expansion of the materials con- 
sumed, or upon the fact that heat expands some 
element, like water, which in turn produces the 
power. One cubic inch of water, when converted 
into steam, has a volume equal to one cubic foot, 
or about 1,700 times increase in bulk. 

Advantage is taken of this in steam engine con- 
struction. If a cylinder has a piston in it with 
an area of 100 square inches, and a pipe one inch 
square supplies steam at 50 pounds pressure, the 
piston will have 50 pounds pressure on every 
square inch of its surface, equal to 5,000 pounds. 



MECHANICAL POWEES 



135 



The Pkessuke oe Head. — In addition to that 
there will also be 50 pounds pressure on each 
square inch of the head, as well as on the sides of 
the cylinder. 

Fig. 131 shows a cylinder (A), a piston (B) and 
a steam inlet port (C), in which is indicated how 




-jP 






Steam Pressure 



i] ^ 
Water Pressure 



the steam pressure acts equally in all directions. 
As, however, the piston is the only movable part, 
the force of the steam is directed to that part, and 
the motion is then transmitted to the crank, and to 
the shaft of the engine. 

This same thing applies to water which, as 
stated, is dependent on its head. Fig. 132 repre- 



136 PEACTICAL MECHANICS FOR BOYS 

sents a cylinder (D) with a vertically movable 
piston (E) and a standpipe (F). Assuming that 
the pipe (F) is of sufficient height to give a pres- 
sure of 50 pounds to the square inch, then the pis- 
ton (E) and the sides and head of the cylinder 
(D) would have 50 pounds pressure on every 
square inch of surface. 

Fuels. — In the use of fuels, such as the volatile 
hydrocarbons, the direct expansive power of the 
fuel gases developed, is used to move the piston 
back and forth. Engines so driven are called In- 
ternal Combustion Motors. 

Power eeom Winds. — Another source of power 
is from the wind acting against wheels which have 
blades or vanes disposed at such angles that there 
is a direct conversion of a rectilinear force into 
circular motion. 

In this case power is derived from the force 
of the moving air and the calculation of energy 
developed is made by considering the pressure 
on each square foot of surface. The following 
table shows the force exerted at different speeds 
against a flat surface one foot square, held so that 
the wind strikes it squarely: 



MECHANICAL POWEES 



137 



SPEED OF WIND 


PRESSURE 


SPEED OF WIND 


PRESSURE 


5 Miles per hour 
10 " 
15 " 
20 " 
25 « 
30 " 


2oz. 

88 « 

lib. 2 « 

2 " 

3 " 2 « 

4 " 8 " 


35 miles per hour 

40 " 

45 " 

50 « 

55 " 

60 " 


6 lb. 2 oz. 

8 « 

10 " 2 « 
12 « 2 " 
15 " 2 « 
18 " 



Vaeying Degkees of Pkessuee. — It is curious to 
notice how the increase in speed changes the pres- 
sure against the blade. Thus, a wind blowing 20 
miles an hour shows 2 pounds pressure ; whereas a 
wind twice that velocity, or 40 miles an hour, 
shows a pressure of 8 pounds, which is four times 
greater than at 20 miles. 

It differs, therefore, from the law with respect 
to water pressure, which is constant in relation to 
the height or the head — that is, for every 28 inches 
height of water a pound pressure is added. 

Power from Waves and Tides. — Many attempts 
have been made to harness the waves and the tide 
and some of them have been successful. This ef- 
fort has been directed to the work of converting 
the oscillations of the waves into a rotary motion, 
and also to take advantage of the to-and-f ro move- 
ment of the tidal flow. There is a great field in 
this direction for the ingenious boy. 

A Profitable Field. — In no direction of human 



138 PEACTICAL MECHANICS FOR BOYS 

enterprise is there such a wide and profitable field 
for work, as in the generation of power. It is 
constantly growing in prominence, and calls for 
the exercise of the skill of the engineer and the 
ingenuity of the mechanic. Efficiency and econ- 
omy are the two great watchwords, and this is 
what the world is striving for. Success will come 
to him who can contribute to it in the smallest 
degree. 

Capital is not looking for men who can cheapen 
the production of an article 50 per cent., but 1 
per cent. The commercial world does not expect 
an article to be 100 per cent, better. Five per cent, 
would be an inducement for business. 



1 



CHAPTER XII 

ON MEASURES 

HoESE-PowER. — When work is performed it is 
designated as horse-power, usually indicated by 
the letters H. P. ; but the unit of work is called a 
foot pound. 

If one pound should be lifted 550 feet in one sec- 
ond, or 550 pounds one foot in the same time, it 
would be designated as one horse-power. For 
that reason it is called a foot pound. Instead of 
using the figure to indicate the power exerted dur- 
ing one minute of time, the time is taken for a 
minute, in all calculations, so that 550 multiplied 
by the number of seconds, 60, in a minute, equals 
33,000 foot pounds. 

Foot Pounds. — The calculation of horse-power 
is in a large measure arbitrary. It was deter- 
mined in this way: Experiments show that the 
heat expended in vaporizing 34 pounds of water 
per hour, develops a force equal to 33,000 foot 
pounds ; and since it takes about 4 pounds of coal 
per hour to vaporize that amount of water, the 
heat developed by that quantity of coal develops 
the same force as that exercised by an average 
horse exerting his strength at ordinary work. 

43 139 



140 PEACTICAL MECHANICS FOE BOYS 

All power is expressed in foot pounds. Sup- 
pose a cannon ball of sufficient weight and speed 
strikes an object. If the impact should indicate 
33,000 pounds it would not mean that the force 
employed was one horse-power, but that many 
foot pounds. 

If there should be 60 impacts of 550 pounds 
each within a minute, it might be said that it 
would be equal to 1 horse-power, but the correct 
way to express it would be foot pounds. 

So in every calculation, where power is to be 
calculated, first find out how many foot pounds 
are developed, and then use the unit of measure, 
33,000, as the divisor to get the horse-power, if 
you wish to express it in that way. 

It must be understood, therefore, that horse- 
power is a simple unit of work, whereas a foot 
pound is a compound unit formed of a foot paired 
with the weight of a pound. 

Enekgy. — Now work and energy are two differ- 
ent things. Work is the overcoming of resistance 
of any kind, either by causing or changing motion, 
or maintaining it against the action of some other 
force. 

Energy, on the other hand, is the power of doing 
work. Falling water possesses energy; so does a 
stone poised on the edge of a cliff. In the case 
of water, it is called kinetic energy; in the stone 



ON MEASUEES 141 

potential energy. A pound of pressure against 
the stone will cause the latter, in falling, to develop 
an enormous energy; so it will be seen that this 
property resides, or is within the thing itself. It 
will be well to remember these definitions. 

How TO Find Out the Power Developed. — The 
measure of power produced by an engine, or other 
source, is so interesting to boys that a sketch is 




3f^. 




T 



^ ZfiarriGter 4'- ^s- JF^ha I^d, 



given of a Prony Brake, which is the simplest 
form of the Dynamometer, as these measuring ma- 
chines are called. 

In the drawing (A) is the shaft, with a pulley 
(A'), which turns in the direction of the arrow 
(B). C is a lever which may be of any length. 
This has a block (CO, which fits on the pulley, and 
below the shaft, and surrounding it, are blocks 
(D) held against the pulley by a chain (E), the 
ends of the chain being attached to bolts (F) which 
pass through the block (C) and lever (C). 



142 PEACTICAL MECHANICS FOR BOYS 

Nuts (G) serve to draw tlie bolts upwardly and 
thus tighten the blocks against the shaft. The 
free end of the lever has stops (H) above and be- 
low, so as to limit its movement. Weights (I) are 
suspended from the end of the lever. 




Fig. 13 Jf. Speed Indicator 



The Test. — The test is made as follows : The 
shaft is set in motion, and the nuts are tightened 
until its full power at the required speed is bal- 
anced by the weight put on the platform. 

The following calculation can then be made : 

For our present purpose we shall assume that 
the diameter of the pulley (A') is 4 inches; the 
length of the lever (C), 3 feet; the speed of the 
shaft (A) and the pulley, 210 revolutions per min- 
ute; and the weight 600 pounds. 

Now proceed as follows: 

(1) Multiply the diameter of the pulley (A') 



ON MEASUEES 143 

(4 inches) by 3.1416, and this will give the circum- 
ference 12.5664 inches ; or, 1.0472 feet. 

(2) Multiply this product (1.0472) by the revo- 
lutions per minute. 1.0472 X 210 = 219.912. This 
equals the speed of the periphery of the pulley. 

(3) The next step is to get the length of the 
lever (C) from the center of the shaft (A) to the 
point from which the weights are suspended, and 
divide this by one-half of the diameter of the pulley 
(A'). 36" -f- 2" = 18'', or li feet. This is the 
leverage. 

(4) Then multiply the weight in pounds by the 
leverage, 600 X I4 = 900. 

(5) Next multiply this product (900) by the 
speed, 900X219.912 = 197,920.8, which means 
foot pounds, 

(6) As each horse-power has 33,000 foot pounds, 
the last product should be divided by this figure, 
and we have 197,920.8 -^ 33,000 = 5.99 H. P. 

The Foot Measuke. — How long is a foot, and 
what is it determined by ? It is an arbitrary meas- 
ure. The human foot is the basis of the measure- 
ment. But what is the length of a man's foot? 
It varied in different countries from 9 to 21 inches. 

In England, in early days, it was defined as 
a measure of length consisting of 12 inches, or 36 
barleycorns laid end to end. But barleycorns dif- 
fer in length as well as the human foot, so the 



144 PEACTICAL MECHANICS FOE BOYS 

standard adopted is without any real foundation 
or reason. 

Weight. — To determine weight, however, a sci- 
entific standard was adopted. A gallon contains 
8.33 pounds avoirdupois weight of distilled water. 
This gallon is divided up in two ways; one by 
weight, and the other by measurement. 

Each gallon contains 231 cubic inches of dis- 
tilled water. As it has four quarts, each quart 
has 57f cubic inches, and as each quart is com- 
prised of two pints, each pint has nearly 29 cubic 
inches. 

The Gallon. — The legal gallon in the United 
States is equal to a cylindrical measure 7 inches 
in diameter and 6 inches deep. 

Notwithstanding the weights and dimensions of 
solids and liquids are thus fixed by following a 
scientific standard, the divisions into scruples, 
grains, pennyweights and tons, as well as cutting 
them up into pints, quarts and other units, is done 
without any system, and for this reason the need 
of a uniform method has been long considered by 
every country. 

The Metkic System. — As early as 1528, Fernal, 
a French physician, suggested the metric system. 
Our own government recognized the value of this 
plan when it established the system of coinage. 

The principle lies in fixing a unit, such as a dol- 



ON MEASUEES 145 

lar, or a pound, or a foot, and then making all 
divisions, or addition, in multiples of ten. Thus, 
we have one mill ; ten mills to make a dime ; ten 
dimes to make a dollar, and so on. 

Basis of Measukement. — The question arose, 
what to use as the basis of measurement, and it 
was proposed to use the earth itself, as the meas- 
ure. For this purpose the meridian line running' 
around the earth at the latitude of Paris was 
selected. 

One-quarter of this measurement around the 
globe was found to be 393,707,900 inches, and this 
was divided into 10,000,000 parts. Each part, 
therefore, was a little over 39.37 inches in length, 
and this was called a meter, which means measure. 

A decimeter is one-tenth of that, namely, 3.927 
inches; and a decameter 39.27, or ten times the 
meter, and so on. 

For convenience the metrical table is given, 
showing lengths in feet and inches, in which only 
three decimal points are used. 

Metrical Table, showing measurements in feet 
and inches : 



146 PEACTICAL MECHANICS FOR BOYS 

METRICAL TABLE, SHOWING MEASUREMENTS IN FEET 
AND INCHES 



Length 


Inches 


Feet 


Millimeter 


0.039 

0.393 

3.937 

39.370 

393.707 

3937.079 

39370.790 

393707.900 


0.003 


Centimeter 

Decimeter 


0.032 
0.328 


Meter 


3.280 


Decameter 


32.808 


Hectometer 

Kilometer 


328.089 
3280 . 899 


Myriameter 


32808.992 







METRIC SYSTEM, SHOWING THE EQUIVA- 
LENTS IN OUR MEASURES 



1 Myriameter 

1 Kilometer 

1 Hectometer 
1 Decameter 
1 Meter 

1 Decimeter 
1 Centimeter 
1 Millimeter 
1 Micron 
1 Hectare 
1 Arc 
1 Centaire, 
meter 



or square 



5.4 nautical miles, or 6.21 stat- 
ute miles. 

0.621 statute mile, or nearly ^ 
mile. 

109.4 yards. 

0.497 chain, 1.988 rods. 

39.37 inches, or nearly 3 ft. 3^ 
inches. 

3.937 inches. 

0.3937 inch. 

0.03937 inch. 

1.25400 inch. 

2.471 acres. 

119.6 square yards. 

= 10.764 square feet. 



ON MEASUEES 



147 



1 Decastere 

1 Stere, or cubic meter 

1 Decistere 
1 Kiloliter 

1 Hectoliter 

1 Decaliter 

1 Liter 

1 Decileter 

1 Millier 

1 Metric quintal 

1 Kilogram 

1 Hectogram 

1 Decagram 
1 Gram 
1 Decigram 
1 Centigram 
1 Milligram 



= 13 cubic yards, or about 2^ 
cords. 

= 1.308 cubic yards, or 35.3 cubic 
feet. 

= 3}^ cubic feet. 

= 1 ton, 12 gal., 2 pints, 2 gills 
old wine measure. 

= 22.01 Imperial gals., or 26.4 
U. S. gals. 

= 2 gallons, 1 pint, 21 gills, im- 
perial measure, or 2 gals., 2 
qts., 1 pt., H gill, U. S. 

= 1 pint, 3 gills, imperial, or 1 qt., 
J^ gill U. S. measure. 

= 0.704 gill, imperial, or 0.845 gill 
U. S. measure. 

= 2,204.6 pounds avoirdupois. 

= 2 hundredweight, less 3J^ 
pounds, or 220 pounds, 7 
ounces. 

= 2 pounds, 3 ounces, 4^ 
drams avoirdupois. 

= 3 ounces, 8^ drams avoirdu- 
pois. 

= 154.32 grains Troy. 

= 15.432 grains. 

= 1.542 grain. 

= 0.154 grain. 

= 0.015 grain. 



CHAPTER XIII 

USEFUL INFORMATION FOR THE WORKSHOP 

To find tlie circumference of a circle : Multiply 
the diameter by 3.1416. 

To find the diameter of a circle : Multiply the 
circle by .31831. 

To find the area of a circle: Multiply the 
square of the diameter by .7854. 

To find the area of a triangle: Multiply the 
base by one-half the perpendicular height. 

To find the surface of a ball: Multiply the 
square of the diameter by 3.1416. 

To find the solidity of a sphere: Multiply the 
cube of the diameter by .5236. 

To find the cubic contents of a cone : Multiply 
the area of the base by one-third the altitude. 

Doubling the diameter of a pipe increases its 
capacity four times. 

To find the pressure in pounds per square inch 
of a column of water : Multiply the height of the 
column in feet by .434. 

Standard Horse-power : The evaporation of 30 
pounds of water per hour from a feed water tem- 
perature of 1,000 degrees Fahrenheit into steam 
at 70 pounds gauge pressure. 

148 



USEFUL INFOEMATION 149 

To find the capacity of any tank in gallons: 
Square the diameter in inches, multiply by the 
length, and then by .0034. 

In making patterns for aluminum castings pro- 
vision must be made for shrinkage to a greater 
extent than with any other metal or alloy. 

The toughness of aluminum can be increased 
by adding a small per cent, of phosphorus. 

All alloys of metals having mercury are called 
amalgams. 

A sheet of zinc suspended in the water of a 
boiler will produce an electrolytic action and pre- 
vent scaling to a considerable extent. 

Hydrofluoric acid will not affect a pure diamond, 
but will dissolve all imitations. 

A strong solution of alum put into glue will 
make it insoluble in water. 

A grindstone with one side harder than the 
other can have its flinty side softened by immers- 
ing that part in boiled linseed oil. 

One barrel contains 3f cubic feet. 

One cubic yard contains 7J barrels. 

To find the speed of a driven pulley of a given 
diameter: ' Multiply the diameter of the driving 
pulley by its speed or number of revolutions. Di- 
vide this by the diameter of the driven pulley. 
The result will be the number of revolutions of the 
driven pulley. 



150 PEACTICAL MECHANICS FOR BOYS 

To find tlie diameter of a driven pnlley that 
sliall make any given number of revolutions in the 
same time : Multiply the diameter of the driving 
pulley by its number of revolutions, and divide 
the product by the number of revolutions of the 
driven pulley. 

A piece of the well-known tar soap held against 
the inside of a belt while running will prevent it 
from slipping, and will not injure the belt. 

Boiler scale is composed of the carbonate or the 
sulphate of lime. To prevent the formation it is 
necessary to use some substance which will pre- 
cipitate these elements in the water. The cheap- 
est and most universally used for this purpose are 
soda ash and caustic soda. 

Gold bronze is merely a mixture of equal parts 
of oxide of tin and sulphur. To unite them they 
are heated for some time in an earthen retort. 

Rusted utensils may be cleaned of rust by apply- 
ing either turpentine or kerosene oil, and allowing 
them to stand over night, when the excess may 
be wiped off. Clean afterwards with fine emery 
cloth. 

Plaster of paris is valuable for many purposes in 
a machine shop, but the disadvantage in handling 
it is, that it sets so quickly, and its use is, there- 
fore, very much limited. To prevent quick setting 
mix a small amount of arrow root powder with 



USEFUL INFOEMATION 151 

the plaster before it is mixed, and this will keep 
it soft for some time, and also increase its hard- 
ness when it sets. 

For measuring purposes a tablespoon holds 
i ounce; a dessertspoon J ounce; a teaspoon ^ 
ounce; a teacupful of sugar weighs J pound; two 
teacupsful of butter weigh 1 pound; 1^ pints of 
powdered sugar weigh 1 pound; one pint of dis- 
tilled water weighs 1 pound. 

Ordinarily, 450 drops of liquid are equal to 1 
ounce; this, varies with different liquids, some 
being thicker in consistency than others, but for 
those of the consistency of water the measure 
given is fairly accurate. 



V. 



CHAPTER XIV 



THE SIMPLICITY OF GREAT INVENTIONS, AND OF 

nature's manifestations 



If there is anything in the realm of mechanics 
which excites the wonder and admiration of man, 
it is the knowledge that the greatest inventions are 
the simplest, and that the inventor must take advan- 
tage of one law in nature which is universal in its 
application, and that is vibration. 

There is a key to every secret in nature's great 
storehouse. It is not a complicated one, containing 
a multiplicity of wards and peculiar angles and 
recesses. It is the very simphcity in most of the 
problems which long served as a bar to discovery 
in many of the arts. So extremely simple have 
been some of the keys that many inventions re- 
sulted from accidents. 

Invention Precedes Science. — Occasionally 
inventions were brought about by persistency and 
energy, and ofttimes by theorizing; but science 
rarely ever aids invention. The latter usually pre- 
cedes science. Thus, reasoning could not show how 
it might be possible for steam to force water into 
a boiler against its own pressure. But the injector 
does this. 

152 



SIMPLICITY OF GREAT INVENTIONS 153 

If, prior to 1876, it had been suggested that a 
sonorous vibration could be converted into an elec- 
trical pulsation, and transformed back again to a 
sonorous vibration, science would have proclaimed 
it impossible ; but the telephone does it. Invention 
shows how things are done, and science afterwards 
explains the phenomena and formulates theories 
and laws which become serviceable to others in the 
arts. 

Simplicity in Inventions. — But let us see how 
exceedingly simple are some of the great discover- 
ies of man. 

The Telegkaph. — The telegraph is nothing but 
a magnet at each end of a wire, with a lever for an 
armature, which opens and closes the circuit that 
passes through the magnets and armature, so that 
an impulse on the lever, or armature, at one end, 
by making and breaking the circuit, also makes and 
breaks the circuit at the other end. 

Telephone. — The telephone has merely a disk 
close to but not touching the end of a magnet. The 
sonorous vibration of the voice oscillates the dia- 
phragm, and as the diaphragm is in the magnetic 
field of the magnet, it varies the pressure, so called, 
causing the diaphragm at the other end of the wire 
to vibrate in unison and give out the same sound 
originally imparted to the other diaphragm. 

Transmitter. — The transmitter is merely a sen- 



154 PEACTICAL MECHANICS FOE BOYS 

sitized instrument. It depends solely on the prin- 
ciple of light contact points in an electric circuit, 
whereby the vibrations of the voice are augmented. 

PHo:sroGKAPH. — The phonograph is not an elec- 
trical instrument. It has a diaphragm provided 
centrally with a blunt pin, or stylus. To make the 
record, some soft or plastic material, like wax, or 
tinfoil, is caused to move along so that the point 
of the stylus makes impressions in it, and the vi- 
brations of the diaphragm cause the point to trav- 
erse a groove of greater or smaller indentations. 
When this groove is again presented to the stylus 
the diaphragm is vibrated and gives forth the 
sounds originally imparted to it when the indenta- 
tions were made. 

Wireless Telegraphy. — ^Wireless telegraphy 
depends for its action on what is called induction. 
Through this property a current is made of a high 
electro-motive force, which means of a high voltage, 
and this disturbs the ether with such intensity that 
the waves are sent out in all directions to immense 
distances. 

The great discovery has been to find a mechanism 
sensitive enough to detect the induction waves. The 
instrument for this purpose is called a coherer, in 
which small particles cohere through the action of 
the electric waves, and are caused to fall apart 
mechanically, during the electrical impulses. 




SIMPLICITY OF GEEAT INVENTIONS 155 

PeintiinTG Telegraph. — The printing telegraph 
requires the synchronous turning of two wheels. 
This means that two wheels at opposite ends of a 
wire must be made to turn at exactly the same rate 
of speed. Originally, this was tried by clock work, 
bnt without success commercially, for the reason 
that a pendulum does not beat with the same speed 
at the equator, as at different latitudes, nor at 
altitudes; and temperature also aifects the rate. 
The solution was found by making the two wheels 
move by means of a tuning fork, which vibrates 
with the same speed everywhere, and under all 
conditions. 

Electric Motor. — The direct current electric 
motor depends for its action on the principle that 
likes repel, and unlikes attract. The commutator 
so arranges the poles that at the proper points, in 
the revolution of the armature, the poles are al- 
ways presented to each other in such a way that as 
they approach each other, they are opposites, and 
thus attract, and as they recede from each other 
they repel. A dynamo is exactly the same, except 
that the commutator reverses the operation and 
makes the poles alike as they approach each other, 
and unlike as they recede. 

Steel is simply iron, to which has been added a 
small per cent of carbon. 

Quinine is efficient in its natural state, but it has 

44 



156 PEACTICAL MECHANICS FOE BOYS 

been made infinitely more effectual by the breaking 
up or changing of the molecules with acids. Sul- 
phate of quinine is made by the use of sulphuric 
acid as a solvent. 

Explosions. — Explosions depend on oxygen. 
While this element does not bum, a certain amount 
of it must be present to support combustion. Thus, 
the most inflammable, gas or liquid will not burn 
or explode unless oxygenized. Explosives are made 
by using a sufficient amount, in a concentrated 
form, which is added to the fuel, so that when it is 
ignited there is a sufficient amount of oxygen pres- 
ent to support combustion, hence the rapid explo- 
sion which follows. 

Vibration in Natuee. — The physical meaning of 
vibration is best illustrated by the movement of a 
pendulum. All agitation is vibration. All force 
manifests itself in this way. 

The painful brilliancy of the sun is produced by 
the rapid vibrations of the rays ; the twinkle of the 
distant star, the waves of the ocean when ruffled by 
the winds ; the shimmer of the moon on its crested 
surface ; the brain in thinking ; the mouth in talk- 
ing; the beating of the heart; all, alike, obey the 
one grand and universal law of vibratory motion. 

Qualities of Sound. — Sound is nothing but a 
succession of vibrations of greater or less magni- 
tude. Pitch is produced by the number of vibra- 



SIMPLICITY OF GEEAT INVENTIONS 157 

tions ; intensity by their force ; and quality by tbe 
cbaracter of the article vibrated. 

Since the great telephone controversy which took 
place some years ago there has been a wonderful 
development in the knowledge of acoustics, or 
sounds. It was shown that the slightest sound 
would immediately set into vibration every article 
of furniture in a room, and very sensitive instru- 
ments have been devised to register the force and 
quality. 

The Photogkaphee's Plate. — It is known that 
the chemical action of an object on a photographer's 
plate is due to vibration ; each represents a force of 
diifferent intensity, hence the varying shades pro- 
duced. Owing to the different rates of vibrations 
caused by the different colors, the difficulty has 
been to photograph them, but this has now been 
accomplished. Harmony, or "being in tune," as 
is the common expression, is as necessary in light, 
as in music. 

Some chemicals will bring out or " develop," the 
pictures; others will not. Colors are now photo- 
graphed because invention and science have found 
the harmonizing chemicals. 

QuADKUPLEX Telegraphy. — One of the most re- 
markable of all the wonders of our age is what is 
known as duplex and quadruplex telegraphy* 
Every atom and impulse in electricity is oscillation. 



158 PEACTICAL MECHANICS FOE BOYS 

The current whicli transmits a telegram is desig- 
nated in the science as " vibratory/' 

But how is it possible to transmit two or more 
messages over one wire at the same time 1 It is by- 
bringing into play the harmony of sounds. One 
message is sent in one direction in the key of A ; 
another message in the other direction in B ; and 
so any number may be sent, because the electrical 
vibrations may be tuned, just like the strings of a 
violin. 

Electeic Haemony. — Every sound produces a 
corresponding vibration in surrounding objects. 
While each vibrates, or is capable of transmitting 
a sound given to it by its vibratory powers, it 
may not vibrate in harmony. 

When a certain key of a piano is struck every 
key has a certain vibration, and if we could sepa- 
rate it from the other sounds, it would reflect the 
same sound as the string struck, just the same as 
the walls of a room or the air itself would convey 
that sound. 

But as no two strings in the instrument vibrate 
the same number of times each second, the rapid 
movement of successive sounds of the keys do not 
interfere with each other. If, however, there are 
several pianos in a room, and all are tuned the same 
pitch, the striking of a key on one instrument will 



SIMPLICITY OF GEEAT INVENTIONS 159 

instantly set in vibration the correspondiag 
strings in all the other instruments. 

This is one reason why a piano tested in a music 
wareroom has always a more beautiful and richer 
sound than when in a drawing-room or hall, since 
each string is vibrated by the other instrument. 

If a small piece of paper is balanced upon the 
strings of a violin, every key of the piano may be 
struck, except the one in tune, without affecting the 
paper; but the moment the same key is struck the 
vibration of the harmonizing pitch will unbalance 
the paper. 

The musical sound of C produces 528 vibrations 
per second; D 616, and so on. The octave above 
has double the number of vibrations of the lower 
note. It will thus be understood why discord ia 
music is not pleasant to the ear, as the vibrations 
are not in the proper multiples. 

Odoks. — So with odors. The sense of smell is 
merely the force set in motion by the vibration of 
the elements. An instrument called the odophone 
demonstrates that a scale or gamut exists in flow- 
ers ; that sharp smells indicate high tones and heavy 
smells low tones. Over fifty odors have thus been 
analyzed. 

The treble clef, note E, 4th space, is orange ; note 
D, 1st space below, violet ; note F, 4th space above 
clef, ambergris. To make a proper bouquet, there- 



160 PEACTICAL MECHANICS FOE BOYS 

fore the different odors must be harmonized, jnst 
the same as the notes of a musical chord are se- 
lected. 

A Bouquet of Vibkation^s. — The odophone 
shows that santal, geranium, orange flower and 
camphor, make a bouquet in the key of C. It is 
easy to conceive that a beautiful bouquet means 
nothing more than an agreeable vibratory sensa- 
tion of the olfactory nerves. 

Taste. — So with the sense of taste. The tongue 
is covered with minute cells surrounded by nervous 
filaments which are set in motion whenever any 
substance is brought into contact with the surface. 
Tasting is merely the movement of these filaments, 
of greater or less rapidity. 

If an article is tasteless, it means that these fila- 
ments do not vibrate. These vibrations are of two 
kinds. They may move faster or slower, or they 
may move in a peculiar way. A sharp acute taste 
means that the vibrations are very rapid; a mild 
taste, slow vibrations. 

When a pleasant taste is detected, it is only be- 
cause the filaments are set into an agreeable mo- 
tion. The vibrations in the tongue may become so 
rapid that it will be painful, just as a shriek be- 
comes piercing to the ear, or an intense light daz- 
zling to the eye ; all proceed from the same physical 
force acting on the brain. 



SIMPLICITY OF GREAT INVENTIONS 161 

Color. — Color, that seemingly unexplainable 
force, becomes a simple thing when the principles 
of vibration are applied, and this has been fully ex- 
plained by the spectroscope and its operation. 

When the boy once appreciates that this force, 
or this motion in nature is just as simple as the 
great inventions which have grown out of this mani- 
festation, he will understand that a knowledge 
of these things will enable him to utilize the energy 
in a proper way. 



CHAPTER XV 

WOEKSHOP EECIPES AND FOKMULAS 

In a work of this kind, dealing with the various 
elements, the boy should have at hand recipes or 
formulas for everything which comes within the 
province of his experiments. The following are 
most carefully selected, the objects being to present 
those which are the more easily compounded. 

Adhesives foe Vaeious Uses. — Water-proof 
glue. Use a good quality of glue, and dissolve it 
in warm water, then add one pound of linseed oil 
to eight pounds of the glue. Add three ounces of 
nitric acid. 

Leather or Card-board Glue. After dissolving 
good glue in water, to which a little turpentine has 
been added, mix it with a thick paste of starch, the 
proportion of starch to glue being about two to 
every part of glue used. The mixture is used cold. 

A fine Belt Glue. Dissolve 50 ounces of gelatine 
in water, and heat after pouring off the excess wa- 
ter. Then stir in five ounces of glycerine, ten 
ounces of turpentine, and five ounces of linseed oil 
varnish. If too thick add water to suit. 

For cementing Iron to Marble. Use 30 parts of 
Plaster of Paris, 10 parts of iron filings, and one 

162 



1 
1 



WORKSHOP RECIPES, FORMULAS 163 

half part of sal ammomac. These are raixed up 
with vinegar to make a fluid paste. 

To cement Glass to Iron. Use 3 ounces of boiled 
linseed oil and 1 part of copal varnish, and into 
this put 2 ounces of litharge and 1 ounce of white 
lead and thoroughly mingle so as to make a smooth 
paste. 

Water-proof Cement. Boiled linseed oil, 6 
ounces; copal, 6 ounces; litharge, 2 ounces; and 
white lead, 16 ounces. To he thoroughly incor- 
porated. 

To unite rubber or leather to hard substances. 
One ounce of pulverized gum shellac dissolved in 
9J ounces of strong ammonia, will make an elastic 
cement. Must be kept tightly corked. 

For uniting iron to iron. Use equal parts of 
boiled oil, white lead, pipe clay and black oxide of 
manganese, and form it into a paste. 

Transparent Cement. Unite 1 ounce of india 
rubber, 67 ounces of chloroform, and 40 ounces of 
mastic. This is to be kept together for a week, and 
stirred at times, when it will be ready for use. 

To Attach Cloth to Metal. Water 100 parts, 
sugar 10 parts, starch 20 parts, and zinc chloride 
1 part. This must be first stirred and made free 
of lumps, and then heated until it thickens. 

United States Government Gum. Dissolve 1 part 
of gum arable in water and add 4 parts of sugar 



164 PEACTICAL MECHANICS FOR BOYS 

and 1 part of starch. This is then boiled for a 
few minutes, and thinned down as required. 

To Make Diffeeent Alloys. — Silver-alumi- 
num. Silver one-fourth part, and aluminum three- 
fourth parts. 

Bell-metal. Copper, 80 parts ; tin, 20 parts. Or, 
copper, 72 parts ; tin, 26 parts ; zinc, 2 parts. Or, 
copper 2 ; 1 of tin. 

Brass. Copper, 66 parts; zinc, 32 parts; tin, 
1 part ; lead, 1 part. 

Bronzes. Copper, 65 parts ; zinc, 30 parts ; tin, 
5 parts. Or, copper, 85 parts ; zinc, 10 parts ; tin, 
3 parts ; lead, 2 parts. 

German Silver. 52 parts of copper; 26 parts 
zinc ; 22 parts nickel. 

For Coating Mirrors. Tin, 70 parts; mercury, 
30 parts. 

BoiLEE Compounds. — To prevent scaling. Use 
common washing soda, or Glauber salts. 

To Dissolve Celluloid. — Use 50 parts of alco- 
hol and 5 parts of camphor for every 5 parts of 
celluloid. When the celluloid is put into the so- 
lution it will dissolve it. 

To Soften Celluloid. This may be done by sim- 
ply heating, so it will bend, and by putting it in 
steam, it can be worked like dough. 

Clay Mixture for Forges. — Mix dry 20 parts 
of fire clay, 20 parts cast-iron turnings, one part 



WOEKSHOP EECIPES, FORMULAS 165 

of common salt, and i part sal ammoniac, and then 
add water while stirring, so as to form a mortar 
of the proper consistency. The mixture will be- 
come very hard when heat is applied. 

A Modeling Clay. This is made by mixing the 
clay with glycerine and afterwards adding vase- 
line. If too much vaseline is added it becomes too 
soft. 

Fluids foe Cleaning Clothes, Fuknituke, Etc. 
— For Delicate Fabrics. Make strong decoction of 
soap bark, and put into alcohol. 

Non-inflammable Cleaner. Equal parts of 
acetone, ammonia and diluted alcohol. 

Taking dried paint from clothing. Shake up 
2 parts of ammonia water with 1 part of spirits of 
turpentine. 

Cleaning Furniture, etc. Unite 2.4 parts of 
wax ; 9.4 parts of oil of turpentine ; 42 parts acetic 
acid; 42 parts citric acid; 42 parts white soap. 
This must be well mingled before using. 

Removing Rust from Iron or Steel. Rub the 
surface with oil of tartar. Or, apply turpentine 
or kerosene, and after allowing to stand over night, 
clean with emery cloth. 

For Removing Ink Stains from Silver. Use a 
paste made of chloride of lime and water. 

To clean Silver-Plated Ware. Make a mixture 
of cream of tartar, 2 parts; levigated chalk, 2 



166 PEACTICAL MECHANICS FOE BOYS 

parts; and alum, 1 part. Grind up the alum and 
mix thoroughly. 

Cleaning a Gas Stove. Make a solution of 9 
parts of caustic soda and 150 parts of water, and 
put the separate parts of the stove in the solution 
for an hour or two. The parts will come out look- 
ing like new. 

Cleaning Aluminum. A few drops of sulphuric 
acid in water will restore the luster to aluminum 
ware. 

Oil Eradicator. Soap spirits, 100 parts ; ammo- 
nia solution, 25 ; acetic ether, 15 parts. 

Disinfectants. — Camphor, 1 ounce; carbolic 
acid (75 per cent.), 12 ounces; aqua ammonia, 10 
drachms ; soft salt water, 8 drachms. 

Water-Closet Deodorant. Ferric chloride, 4 
parts; zinc chloride, 5 parts; aluminum chloride, 
4 parts; calcium chloride, 5 parts; magnesium 
chloride, 3 parts; and water sufficient to make 90 
parts. T\^en all is dissolved add to each gallon 
10 grains of thymol and a quarter-ounce of rose- 
mary that had been previously dissolved in six 
quarts of alcohol. 

Odorless Disinfectants. Mercuric chloride, 1 
part; cupric sulphate, 10 parts; zinc sulphate, 50 
parts; sodium chloride, 65 parts; water to make 
1,000 parts. 

Emery for Lapping Purposes. Fill a pint bottle 



WOEKSHOP EECIPES, FOEMULAS 167 

with machine oil and emery flour, in the propor- 
tion of 7 parts oil and 1 part emery. Allow it to 
stand for twenty minutes, after shaking up well, 
then pour off half the contents, without disturb- 
ing the settlings, and the part so poured off con- 
tains only the finest of the emery particles, and 
is the only part which should be used on the lap- 
ping roller. 

Explosives. — Common Gunpowder. Potassium 
nitrate, 75 parts; charcoal, 15 parts; sulphur, 10 
parts. 

Dynamite. 75 per cent, nitro-glycerine ; 25 per 
cent, infusorial earth. 

Giant Powder. 36 per cent, nitro-glycerine ; 48 
per cent, nitrate of potash ; 8 per cent, of sulphur ; 
8 per cent, charcoal. 

Fulminate. Chlorate of potassia, 6 parts ; pure 
lampblack, 4 parts ; sulphur, 1 part. A blow will 
cause it to explode. 

Files. — How to Keep Clean. Olive oil is the 
proper substance to rub over files, as this will pre- 
vent the creases from filling up while in use, and 
preserve the file for a longer time, and also enable 
it to do better cutting. 

To Eenew Old Files. Use a potash bath for boil- 
ing them in, and afterwards brush them well so 
as to get the creases clean. Then stretch a cotton 
cloth between two supports, and after plunging the 



168 PEACTICAL MECHANICS FOE BOYS 

file into nitric acid, use the stretched cloth to wipe 
off the acid. The object is to remove the acid 
from the ridges of the file, so the acid will only eat 
out or etch the deep portions between the ridges, 
and not affect the edges or teeth. 

FiEE Peoof Mateeials oe Substances. — For 
Wood. For the kind where it is desired to apply 
with a brush, use 100 parts sodium silicate; 50 
parts of Spanish white, and 100 parts of glue. It 
must be applied hot. 

Another good preparation is made as follows: 
Sodium silicate, 350 parts ; asbestos, powdered, 350 
parts ; and boiling water 1,000 parts. 

For Coating Steel, etc. Silica, 50 parts ; plastic 
fire clay, 10 parts ; ball clay, 3 parts. To be thor- 
oughly mixed. 

For Paper. Ammonium sulphate, 8 parts ; boracic 
acid, 3 parts; borax, 2 parts; water, 100 parts. 
This is applied in a liquid state to the paper sur- 
face. 

Flooe Deessings. — Oil Stain. Neats' foot oil, 1 
part; cottonseed oil, 1 part; petroleum oil, 1 part. 
This may be colored with anything desired, like 
burnt sienna, annatto, or other coloring material. 

Ballroom Powder. Hard paraffine, 1 pound; 
powdered boric acid, 7 pounds ; oil of lavender, 1 
drachm; oil of neroli, 20 minims. 

Foot Powdees. — For Perspiring Feet. Balsam 



WOEKSHOP EECIPES, FOEMULAS 169 

Peru, 15 minims; formic acid, 1 drachm; chloral 
hydrate, 1 drachm ; alcohol to make 3 ounces. 

For Easing Feet. Tannaform, 1 drachm; tal- 
cum, 2 drachms; lycopodium, 30 grains. 

Frost Bites. Carbolized water, 4 drachms ; ni- 
tric acid, 1 drop; oil of geranium, 1 drop. 

Glass. — To cut glass, hold it under water, and 
use a pair of shears. 

To make a hole through glass, place a circle of 
moist earth on the glass, and form a hole in this 
the diameter wanted for the hole, and in this hole 
pour molten lead, and the part touched by the lead 
will fall out. 

To Frost Glass. Cover it with a mixture of 6 
ounces of magnesium sulphate, 2 ounces of dex- 
trine, and 20 ounces of water. This produces a 
fine effect. 

To imitate ground glass, use a composition of 
sandarac, 2^ ounces; mastic, i ounce; ether, 24 
ounces; and benzine, 16 ounces. 

Ieon and Steel. — How to distinguish them. 
Wash the metal and put it into a solution of bi- 
chromate of potash to which has been added a 
small amount of sulphuric acid. In a minute or so 
take out the metal, wash and wipe it. Soft steel 
and cast iron will have the appearance of an ash- 
gray tint ; tempered steels will be black ; and pud- 



170 PEACTICAL MECHANICS FOR BOYS 

died or refined irons will be nearly white and have 
a metallic reflection. 

To Harden Iron or Steel. If wrought iron, put 
in the charge 20 parts, by weight, of common salt. 
2 parts of potassium cyanide, .3 part of potas- 
sium bichromate, .15 part of broken glass. 

To harden cast iron, there should be added to 
the charge the following: To 60 parts of water, 
add 2J parts of vinegar, 3 parts of common salt, 
and .25 part of hydrochloric acid. 

To soften castings: Heat them to a high tem- 
perature and cover them with fine coal dust and 
allow to cool gradually. 

Lacqueks. — For Aluminum. Dissolve 100 parts 
of gum lac in 300 parts of ammonia and heat for 
an hour moderately in a water bath. The alumi- 
num must be well cleaned before applying. Heat 
the aluminum plate afterwards. 

For Brass. Make a compound as follows; An- 
natto, I ounce ; saffro, ^ ounce ; turmeric, 1 ounce ; 
seed lac, 3 ounces ; and alcohol, 1 pint. Allow the 
mixture to stand for three days, then strain in the 
vessel which contains the seed lac, and allow to 
stand until all is dissolved. 

For Copper. Heat fine, thickly liquid amber 
varnish so it can be readily applied to the copper, 
and this is allowed to dry. Then heat the coated 
object until it commences to smoke and turn brown. 



WOEKSHOP EECIPES, FOEMULAS 171 

Lubricants. — Heavy machinery oils. Use paraf- 
fine, 8 pounds ; palm oil, 20 pounds ; and oleonap- 
tha, 12 pounds. Dissolve the paraffine in the oleo- 
naptha at a temperature of 160 degrees and then 
stir in the palm oil a little at a time. 

For Cutting Tools. Heat six gallons of water 
and put in three and a half pounds of soft soap 
and a half gallon of clean refuse oil. It should be 
well mixed. 

For high-speed bearings. Use flaky graphite 
and kerosene oil. Apply this as soon as there is 
any indication of heating in the bearings. 

For lathe centers, one part of graphite and four 
parts of tallow thoroughly mixed and applied will 
be very serviceable. 

For Wooden Gears. Use tallow, 30 parts ; palm 
oil; 20 parts; fish oil, 10 parts; and graphite, 20 
parts. 

Paper. — Fire Proof Paper.— Make the following 
solution: Ammonium sulphate, 8 parts; boracie 
acid, 3 parts; water, 100 parts. Mix at a temper- 
ature of 120 degrees. Paper coated with this will 
resist heat. 

Filter Paper. Dip the paper into nitric acid of 
1.433 specific gravity, and subsequently wash and 
dry it. This makes a fine filtering body. 

Carbon Paper. A variety of substances may be 
used, such as fine soot or ivory black, ultramarine 

45 



172 PEACTICAL MECHANICS FOE BOYS 

or Paris blue. Mix either with fine grain soap, 
so it is of a uniform consistency and then apply 
to the paper with a stiff brush, rubbing it in until 
it is evenly spread over the surface. 

Tracing Paper. Take unsized paper and apply 
a coat of varnish made of equal parts of Canada 
balsam and oil of turpentine. To increase the 
transparency give another coat. The sheets must 
be well dried before using. 

Photogkaphy. — Developers. 

1. Pure water, 30 ounces; sulphite soda, 5 
ounces; carbonate soda, 2^ ounces. 

2. Pure water, 24 ounces; oxalic acid, 15 
grains; pyrogallic acid, 1 ounce. 

To develop use of solution 1, 1 ounce; solution 
2, i ounce ; and water, 3 ounces. 

Stock solutions for developing: Make solution 
No. 1 as follows: water, 32 ounces; tolidol, 1 
ounce ; sodium sulphate, IJ ounces. 

Solution No. 2: Water, 32 ounces; sodium sul- 
phate. 

Solution No. 3 : Water, 32 ounces ; sodium car- 
bonate, from 4 to 6 ounces. 

Fixing bath. Add two ounces of S. P. C. clarifier 
(acid bisulphate of sodium) solution to one quart 
of hypo solution 1 in 5. 

Clearing solution. Saturated solution of alum, 
20 ounces; and hydrochloric acid, 1 ounce. 



WORKSHOP RECIPES, FORMULAS 173 

Varnish. Brush over the negative a solution of 
equal parts of benzol and Japanese gold size. 

Plasters. — Court Plaster. Use good quality 
silk, and on this spread a solution of isinglass 
warmed. Dry and repeat several times, then ap- 
ply several coats of balsam of Peru. Or, 
• On muslin or silk properly stretched, apply a 
thin coating of smooth strained flour paste, and 
when dry several coats of colorless gelatine are 
added. The gelatine is applied warm, and cooled 
before the fabric is taken oif . 

Plating. — Bronze coating. For antiques, use 
vinegar, 1,000 parts; by weight, powdered blood- 
stone, 125 parts ; plumbago, 25 parts. Apply with 
brush. 

For brass where a copper surface is desired, 
make a rouge with a little chloride of platinum and 
water, and apply with a brush. 

For gas fixtures. Use a bronze paint and mix 
with it five times its volume of spirit of turpen- 
tine, and to this mixture add dried slaked lime, 
about 40 grains to the pint. Agitate well and de- 
cant the clear liquid. 

Coloring Metals. — Brilliant black for iron. 
Selenious acid, 6 parts ; cupric sulphate, 10 parts ; 
water 1,000 parts ; nitric acid, 5 parts. 

Blue-black. Selenious acid, 10 parts ; nitric acid, 
5 parts ; cupric sulphate ; water, 1,000 parts. The 



174 PEACTICAL MECHANICS FOE BOYS 

colors will be varied dependent on the time the 
objects are immersed in the solution. 

Brass may be colored brown by using an acid 
solution of nitrate of silver and bismuth; or a 
light bronze by an acid solution of nitrate of silver 
and copper; or black by a solution of nitrate of 
copper. 

To copper plate aluminum, take 30 parts of sul- 
phate of copper; 30 parts of cream of tartar; 25 
parts of soda ; and 1,000 parts of water. The article 
to be coated is merely dipped into the solution. 

Polishers. — Floor Polish. Permanganate of 
potash in boiling water, applied to the floor hot, 
will produce a stain, the color being dependent on 
the number of coats. The floor may them be pol- 
ished with beeswax and turpentine. 

For Furniture. Make a paste of equal parts of 
plaster of paris, whiting, pumice stone and lith- 
arge, mixed with Japan dryer, boiled linseed oil 
and turpentine. This may be colored to suit. This 
will fill the cracks of the wood. Afterwards rub 
over the entire surface of the wood mth a mixture 
of 1 part eJapan, 2 of linseed oil, and three parts of 
turpentine, also colored, and after this has been 
allowed to slightly harden, rub it off, and within 
a day or two it will have hardened sufficiently so 
that the surface can be polished. 

Stove Polish. Ceresine, 12 parts; Japan wax, 



WORKSHOP RECIPES, FORMULAS 175 

10 parts; turpentine oil, 100 parts; lampblack, 12 
parts; graphite, 10 parts. Melt the ceresine and 
wax together, and cool off partly, and then add 
and stir in the graphite and lampblack which were 
previously mixed up with the turpentine. 

Putty. — Black Putty. Whiting and antimony 
sulphide, and soluble glass. This can be polished 
finely after hardening. 

Common Putty. Whiting and linseed oil mixed 
up to form a dough. 

Rust Preventive. — For Machinery. Dissolve 
an ounce of camphor in one pound of melted lard. 
Mix with this enough fine black lead to give it an 
iron color. After it has been on for a day, rub off 
with a cloth. 

For tools, yellow vaseline is the best substance. 

For zinc, clean the plate by immersing in water 
that has a small amount of sulphuric acid in it. 
Then wash clean and coat with asphalt varnish. 

Solders. — For aluminum. Use 5 parts of tin 
and 1 part of aluminum as the alloy, and solder 
with the iron or a blow pipe. 

Yellow hard solder. Brass, 34 parts ; and zinc, 
1 part. 

For easily fusing, make an alloy of equal parts 
of brass and zinc. 

For a white hard solder use brass, 12 parts ; zinc, 
1 part ; and tin, 2 parts. 



176 PEACTICAL MECHANICS FOE BOYS 

SoLDEKiNG Fluxes. — For soft soldering, use a 
solution of chloride of zinc and sal ammoniac. 
Powdered rosin is also used. 

For hard soldering, borax is used most fre- 
quently. A mixture of equal parts of cryolite and 
barium chloride is very good in soldering bronze 
or aluminum alloys. 

Other hard solders are alloyed as follows : brass, 
4 parts; and zinc, 5 parts. Also brass, 7 parts; 
and zinc, 2 parts. 

Steel Tempering. — Heat the steel red hot and 
then plunge it into sealing wax. 

For tempering small steel springs, they may be 
plunged into a fish oil which has a small amount of 
rosin and tallow. 

Varnishes. — Black Varnish. Shellac, 5 parts; 
borax, 2 parts ; glycerine, 2 parts ; aniline black, 6 
parts; water, 45 parts. Dissolve the shellac in hot 
water and add the other ingredients at a temper- 
ature of 200 degrees. 

A good can varnish is made by dissolving 15 
parts of shellac, and adding thereto 2 parts of 
Venice turpentine, 8 parts of sandarac, and 75 
parts of spirits. 

A varnish for tin and other small metal boxes is 
made of 75 parts alcohol, which dissolves 15 parts 
of shellac, and 3 parts of turpentine. 

Sealing Wax. — For modeling purposes. White 



\ WORKSHOP RECIPES, FORMULAS 177 

"wax, 20 parts; turpentine, 5 parts; sesame oil, 2 
parts; vermilion, 2 parts. 

Ordinary Sealing. 4 pounds of shellac, 1 pound 
Venice turpentine, add 3 pounds of vermilion. 
Unite by heat. 



CHAPTER XVI 

HANDY TABLES 







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HANDY TABLES 



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180 PEACTICAL MECHANICS FOB BOYS 

AVOIRDUPOIS WEIGHT. 

For Merchandise of all kinds. 

16 Drams (dr.) make 1 Ounce (oz.) 

16 Ounces make 1 Pound (pd.) 

25 Pounds make 1 Quarter (qr.) 

4 Quarters, or 100 lbs., make. . 1 Hundredweight (cwt.) 

20 Hundredweights make 1 Ton (T.) 

2,240 Pounds make 1 Long ton (L. T.) 



TROY WEIGHT. 

For Gold, Silver, and Precious Metals. 

24 Grains (gr.) make .... 1 Pennyweight (pwt.) 
20 Pennyweights make . 1 Ounce (oz.) 
12 Ounces make 1 Pound (pd.) 



APOTHECARIES WEIGHT. 
For Drugs, Medicals and Chemicals. 

20 Grains (gr.) make 1 Scruple (so.) 

3 Scruples make 1 Dram (dr.) 

8 Drams make 1 Ounce (oz.) 

12 Ounces make 1 Pound (pd.) 



HANDY TABLES 181 

LINEAR MEASURE. 
For Surveyors' Use. 

12 Inches make 1 Foot 

3 Feet make 1 Yard 

5J^ Yards make. 1 Rod 

40 Rods make 1 Furlong 

8 Furlongs 1 Mile 



LONG MEASURE. 



12 Inches make 1 Foot 

3 Feet make 1 Yard 

6 Feet make 1 Fathom 

53/2 Yards make 1 Rod or pok 

40 Poles make 1 Furlong 

8 Furlongs make 1 Mile 

3 Miles make 1 League 

693^^ Miles make 1 Degree 



SQUARE MEASURE. 

144 square inches make 1 square foot 

9 square feet make 1 square yard 

30J^ square yards make 1 square pole 

40 square poles make 1 square rod 

4 square rods make 1 acre 

640 square acres make 1 acre mile 



182 PEACTICAL MECHANICS FOR BOYS 

SOLID OR CUBIC MEASURE. 

1,728 Cubic inches make — 1 Cubic foot 

27 Cubic feet make 1 Cubic yard 

128 Cubic feet make 1 Cord of wood 

24% Cubic feet make — 1 Perch of stone 



DRY MEASURE. 



2 Pints make 1 Quart (qt.) 

8 Quarts make. 1 peck (pk.) 

4: Pecks make 1 Bushel (bu.) 

36 Bushels make 1 Chaldron (ch.) 



LIQUID MEASURE. 

4 Gills (g.) make 1 Pint (pt.) 

2 Pints make 1 Quart (qt.) 

4 Quarts make 1 Gallon (gal.) 

31H Gallons make 1 Barrel (bbl.) 

2 Bbls., or 63 gals., make. 1 Hogshead (hhd.) 



PAPER MEASURE. 



24 Sheets (sh.) make 1 Quire (qu.) 

20 Quires make 1 Ream (r.) 

10 Reams make 1 Bale (ba.) or bundle. 



HANDY TABLES 183 



TABLE OF TEMPERATURES. 

Greatest artificial cold 220 degrees below Fahr. 

natural « 73.7 « « " 

Mercury freezes 39 " " *' 

Mixture of snow and salt 4 " " " 

Greatest density of water at . 39 . 2 " above " 

Blood Heat 97.9 " 

Alcohol boils 172.4 " 

Water boils 212 ^ 

Mercury boils 662 " 

Sulphur boils 824 « 

Silver melts 1,749 " 

Cast iron melts 2,786 " 



a 



STRENGTH OF VARIOUS METALS. 

The tests are made by using a cubic inch of the metal 
and compressing it, and by trying to draw apart a square 
inch of metal. Indicated in pounds. 



184 PEACTICAL MECHANICS FOR BOYS 



Tension 



Compression 



Aluminum 

Brass, cast 

Bronze, gun metal 

" manganese 

" phosphor 

Copper, cast 

" wire annealed 

" " unannealed.. . 

Iron, cast 

" " annealed 

" " unannealed 

" wrought 

Lead, cast 

Steel castings 

" plow 

" structural 

" wire annealed 

" '-rucible 

Tin 



15,000 
24,000 
32,000 
60,000 
50,000 
24,000 
36,000 
60,000 
15,000 
60,000 
80,000 
48,000 
2,000 
70,000 

270,000 
60,000 
80,000 

180,000 
3,800 



12,000 

30,000 

20,000 

120,000 



40,000 



80,000 
46,000 
70,000 
60,000 



6,000 



HANDY TABLES 
FREEZING MIXTURES. 



185 



Mixtures 


Temperature Changes in 
Degrees Fahrenheit 




From 


To 


Common salt, 1 part; snow, 3 
parts 

Common salt, 1 part; snow 1 
part 

Calcium chloride, 3 parts; snow 
1 Dart 


32 
32 
32 
32 
50 
46 
50 
32 


zero . 
-.4 
-27 


Calcium chloride, 2 parts; snow 
1 Dart 


-44 


Sal ammoniac, 5 parts; salt- 
peter 5 parts; water 16 parts. 

Sal ammoniac, 1 part; salt- 
peter 1 part; water 1 part. . 

Ammonium nitrate, 1 part; 
water 1 part 

Potassium hydrate, 4 parts; 
snow 3 parts 


-10 
-11 
- 3 
-35 







IGNITION TEMPERATURES. 

Phosphorus 120 degrees Fahrenheit 

Bi-sulphide of carbon 300 

Gun-cotton 430 

Nitro-glycerine 490 

Phosphorus, amorphous 500 

Rifle powder 550 

Charcoal 660 

Dry pine wood 800 

Oak 900 



186 PEACTICAL MECHANICS FOR BOYS 



POWER AND HEAT EQUIVALENTS. 

In studying matters pertaining to power and heat, 
certain terms are used, such as horsepower, horsepower- 
hours, watts, watt-hours, kilowatt, kilowatt-hours, foot- 
pounds, joule, and B. T. U. (British Thermal Unit). 

The following tables give a comprehensive idea of the 
values of the different terms : 

1 Horsepower-hour = 0.746 kilowatt-hour = 1,980,000 
foot-pounds of water evaporated 
at 212 degrees Fahrenheit, raised 
from 62 degrees to 212 degrees. 

1 Kilowatt-hour = 1,000 watt-hours = 1.34 horse- 
power-hours = 2,653,200 foot- 
pounds = 3,600,000 joules = 3,420 
B. T. U. = 3.54 pounds of water 
evaporated at 212 degrees = 22.8 
pounds of water raised from 62 to 
212 degrees. 

1 Horsepower = 746 watts = 0.746 kilowatts = 33,- 

000 foot-pounds per second = 2,550 
B. T. U. per min. = 0.71 B. T. U. 
per second = 2.64 pounds of water 
evaporated per hour at 212 degrees. 

1 Kilowatt = 1,000 watts = 1.34 horsepower = 

2,653,200 foot-pounds per hour = 
44,220 foot-pounds per min. = 737 
foot-pounds per second = 3,420 
B. T. U. per hour = 57 B. T. U. 
per min. = 0.95 B. T. U. per sec- 
ond = 3.54 pounds of water evapo- 
rated per hour at 212. 



HANDY TABLES 187 

1 Watt = 1 joule per second = 0.00134 horse- 

power = 0.001 kilowatt = 342 
B. T. U. per hour = 44.22 foot- 
pounds per min. = 0.74 foot-pounds 
per second = 0.0035 pounds of 
water evaporated per hour at 212 
degrees. 

1 B. T. U. (British Thermal Unit) = 1,052 watt-seconds 
= 778 foot-pounds = 0.252 calorie 
= 0.000292 kilowatt-hours = 0.- 
000391 horsepower-hour = 0.00104 
pounds of water evaporated at 212 
degrees. 

1 Foot-pound = 1.36 joule = 0.000000377 kilowatt- 

• hour = 0.00129 B. T. U. = 0.- 
0000005 horsepower-hour. 

1 Joule = 1 watt-second = 0.000000278 kilo- 

watt-hour = 0.00095 B. T. U. = 
0.74 foot-pounds. 



46 



CHAPTEE XVII 

AND INFOKMATION ABOUT 
THE EIGHTS AND DUTIES OF INVENTOKS 
AND WOEKMEN 

Theee is no trade or occupation which calls 
forth the inventive faculty to a greater degree 
than the machinist's. Whether it be in the direc- 
tion of making some new tool, needed in some spe- 
cial work, or in devising a particular movement, 
or mechanical expedient, the machinist must be 
prepared to meet the issues and decide on the best 
structural arrangement. 

Opportunities also come daily to the workers in 
machine shops to a greater extent than other arti- 
sans, because inventors in every line bring inven- 
tions to them to be built and experimentally 
tested. 

A knowledge of the rights and duties of inven- 
tors, and of the men who build the models, is very 
desirable; and for your convenience we append 
the following information : 

The inventor of a device is he who has conceived 
an idea and has put it into some concrete form. 

A mere idea is not an invention. 

The article so conceived and constructed, must 

188 



INVENTIONS AND PATENTS 189 

be both neiv and useful. There must be some util- 
ity. It may be simply a toy, or something to 
amuse. 

If A has an idea, and he employs and pays 
B to work out the device, and put it into practi- 
cal shape, A is the inventor, although B may 
have materially modiiied, or even wholly changed 
it. B is simply the agent or tool to bring it to 
perfection, and his pay for doing the work is his 
compensation. 

An inventor has two years' time within which he 
may apply for a patent, after he has completed 
his device and begun the sale of it. If he sells the 
article for more than two years before applying 
for a patent, this will bar a grant. 

Two or more inventors may apply for a patent, 
provided each has contributed something toward 
bringing it to its perfected state. Each cannot 
apply separately. The patent issued will be 
owned by them jointly. 

Joint owners of a patent are not partners, un- 
less they have signed partnership papers respect- 
ing the patent. Because they are partners in 
some other enterprise, disconnected from the pat- 
ent, that does not constitute them partners in the 
patent. They are merely joint owners. 

If they have no special agreement with respect 
to the patent each can grant licenses to manufac- 



190 PEACTICAL MECHANICS FOR BOYS 

ture, independently of the others, without being 
compelled to account to the others, and each has a 
right to sell his interest without asking permission 
of the others. 

An inventor is one who has devised an inven- 
tion. A patemtee is one who owns a patent, or an 
interest in one, be he the inventor or not. 

The United States government does not grant 
Caveats. The only protection offered is by way 
of patent. 

A patent runs for a period of seventeen years, 
and may be renewed by act of Congress only, for 
a further term of seven years. 

An interference is a proceeding in the Patent 
Office to determine who is the first inventor of a 
device. The following is a brief statement of the 
course followed: 

When two or more applicants have applications 
pending, which, in the opinion of the Examiner, 
appear to be similar, the Office may declare an 
interference. 

If an applicant has an application pending, and 
the Examiner rejects it on reference to a patent 
already issued, the applicant may demand an in- 
terference, and the Office will then grant a hear- 
ing to determine which of the two is entitled to the 
patent. 

The first step, after the declaration of interfer- 



INVENTIONS AND PATENTS 191 

ence, is to request that each applicant file a pre- 
liminary statement, under oath, in which he must 
set forth the following : 

First : The date of conception of the invention. 

Second: Date of the first reduction to writing, 
or the preparation of drawings. 

Third : Date of making of the first model or de- 
vice. 

Fourth: When a complete machine was first 
produced. 

These statements are filed in the Patent Office, 
and opened on the same day, and times are then 
set for the respective parties to take testimony. 

If one of the parties was the first to conceive 
and reduce to practice, as well as the first to file 
his application, he will be adjudged to be the first 
inventor, without necessitating the taking of testi- 
mony. 

If, on the other hand, one was the first to con- 
ceive, and the other the first to file, then testimony 
will be required to determine the question of in- 
vention. 

The granting of a patent is not conclusive that 
the patentee was, in reality, the first inventor. 
The law is that the patent must issue to the first 
inventor, and if it can be proven that another 
party was the first, a new patent will issue to the 
one who thus establishes his right. The Commis- 



192 PEACTICAL MECHANICS FOE BOYS 

sioner of Patents has no right to take away the 
patent first issued. Only the Courts are com- 
petent to do this. 

A patent is granted for the right to make, to 
use and to vend. 

An owner of a patent cannot sell the right only 
to make, or to sell, or to use. Such a document 
would be a simple license, only, for that particular 
purpose, 

A patent may be sold giving a divided, or an 
undivided right. 

A divided right is where a State, or any other 
particular territorial right is granted. An undi- 
vided right is a quarter, or a half, or some other 
portion in the patent itself. 

If an inventor assigns his invention, and states 
in the granting clause that he conveys "all his 
right and title in and to the invention," or words 
to that effect, he conveys all his rights throughout 
the world. 

If the conveyance says, "all rights and title in 
and throughout the United States," he thereby re- 
serves all other countries. 

If a patent is issued, and the number and date 
of the patent are given, the assignment conveys 
the patent for the United States only, unless for- 
eign countries are specifically mentioned. 

To convey an invention or patent, some definite 



L\vENTIOx\S AND PATENTS 193 

number or filing date must be given in the docu- 
ment, with sufficient clearness and certainty to 
show the intent of the assignor. 

An invention does not depend on quantity, but 
on quality. It is that which produces a new and 
a useful result. 

In the United States patents are granted for the 
purpose of promoting the useful arts and sciences. 

In England, and in many other foreign coun- 
tries, patents are granted, not on account of any 
merit on the part of the inventor, but as a favor 
of the crown, or sovereign. 

Originally patents were granted by the crown 
for the exclusive privilege in dealing in any com- 
modity, and for this right a royal fee was exacted. 
From this fact the term royalty originated. 

An international agreement is now in force 
among nearly all countries, which respects the fil- 
ing of an application in any country, for a period 
of one year in the other countries. 

In making an application for a patent, a peti- 
tion is required, a specification showing its object, 
use, and particular construction, followed by a 
claim, or claims, and accompanied by a drawing, 
if the invention will permit of it, (which must be 
made in black, with India ink), and an oath. 

The oath requires the following assertions : That 
the applicant is the first and original inventor 



194 PEACTICAL MECHANICS FOE BOYS 

of the device, and that he does not know and does 
not believe the same was ever known or used be- 
fore his invention or more than two years before 
his application. 

He must also further allege that the invention 
was not patented or described in any printed pub- 
lication here or abroad, and not manufactured 
more than two years prior to the application, and 
that he has not made an application, nor author- 
ized any one to do so more than two years prior 
to his application. 

The first Government fee is $15, payable at the 
time of filing, and the second and final fee is $20, 
payable at the time the patent is ordered to issue. 

The filing of an application for patent is a se- 
cret act, and the Patent Office will not give any 
information to others concerning it, prior to the 
issue of the patent. 



GLOSSARY OF WORDS 
USED IN TEXT OF THIS VOLUME 



Abrupt. Suddenly; coming without warning. 

Abrasive. A material which wears away. 

Actuate. Influenced, as by sudden motive; incited to action. 

Accumulate. To bring together ; to amass ; to collect. 

Acoustics. The branch of physics which treats of sound. 

Adhesion. To hold together; a molecular force by means of 

which particles stick together. 
Affinity. Any natural drawing together; the property or force 

in chemicals to move toward each other. 
Aggravate. To incite; to make worse or more burdensome. 

Alloy. A combination of two or more metals. 

Altitude. Height; a vertical distance above any point. 

Alkali Any substance which will neutralize an acid, as lime, 

magnesia, and the like. 
Amalgam. Any compound of metal which has mercury as one 

of the elements. 
Amiss. Wrong, fault, misdeed. 

Annealing. A process of gradually heating and cooling metals, 

whereby hardness and toughness are brought about. 
Angle plate. A metal structure which has two bodies, or limbs, 

at right angles to each other. 
Analysis. The separating of substances into their elementary 

forms. 
Anchor bolt. A structure intended to be placed in a hole in a wall, 

and held there by a screw which expands a part 

of the structure. 
195 



196 PEACTICAL MECHANICS FOB BOYS 



Apprentice. One who is learning a trade or occupation. 

Artificial. That which resembles the original; made in imitation 

of. 

Arbor. A shaft, spindle, mandrel, or axle. 

Armature. A metallic body within the magnetic field cf a mag- 

net. 

Arbitrary. Stubborn determination. Doing a thing without re- 

gard to consequences. 

Artisan. One skilled in any mechanical art. 

Attributable. That which belongs to or is associated with. 

Automatically. Operating by its own structure, or without outside 
aid. 

Augmented. Added to; to increase. 

Auxiliary. To aid; giving or furnishing aid. 

Avoirdupois. The system of weights, of which the unit is sixteen 
ounces. 

Back-saw. A saw which has a rib at its upper margin. 

Barleycorn. A grain of barley. 

Bastard. A coarse-grained file. 

B. T. U. British Thermal Unit. 

Back-gear. That gear on a lathe for changing the feed. 

Bevel. Not in a right line; slanting; oblique. 

Bibb. A form of water faucet. 

Bit, or bitt. A form of tool for cutting purposes on a lathe, planer, 

shaper, oi' drilling machine. 

Borax. A white crystalline compound, of a sweetish taste. 

Chemically it is sodium biborate. 

Buffs. Usually a wheel covered with leather or cloth, and 

having emery dust on it, for fine polishing purposes. 

Buffeted. Thrown back. 

Bronze. An alloy of copper and tin. 

Calcium. Lime. 

Cant. A form of lever. 



GLOSSAEY 



197 



Carbonate. A salt of carbonic acid. 

Caustic. Capable of corroding or eating away. 

Capillary. That quality of a liquid which causes it to move 

upwardly or along a solid with which it is in con- 
tact. 

Caliper. An instrument for spanning inside and outside di- 

mensions. 

Centripetal. The force which tends to draw inwardly, or to the 
center. 

Centrifugal. The outwardly-moving force from a body. 

Centering. To form a point equidistant from a circular line. 

Chloride. A compound of chlorine with one or more positive ele- 

ments, such as, for instance, salt. 

Circular pitch. The measurement around a gear taken at a point 
midway between the base and end of the teeth. 

Circuxaference. The outside of a circular body. 

Clef. A character placed on a staff of music to determine 

the pitch. 

Clutch. A mechanical element for attaching one part to an- 

other. 

Chuck, A disk of metal to be attached to the live spindle 

Independent. of a lathe, and which has on its face a set of dogs 
which move radially independently of each other. 

Chuck, A disk to be attached as above, provided with dogs 

Universal. which are connected so they move radially in uni- 

son with each other. 

Classified. Arranged in order, in such a manner that each of a 

kind is placed under a suitable heading. 

Clearance. To provide a space behind the cutting edge of a tool 

which will not touch the work being cut. 

Consistency. Harmonious; not contradictory. 

Coherer. That instrument in a wireless telegraphy apparatus 

which detects the electrical impulses. 



198 PEACTICAL MECHANICS FOR BOYS 



Commutator. 



Concentrated. 
Coinage. 
Compound. 
Constant. 

Conversion. 
Cone. 



Compression. 

Convolute. 

Coiled. 

Conductivity. 



Cohesion. 

Concentric. 

Confined. 

Corpuscular. 

Converge. 

Concave. 

Convex. 

Component. 
Coefficient. 

Cube. 



The cylindrical structure on the end of an armature, 

whicli is designed to change the polarity of the 

current. 
Brought together at one point. 
The system of making money from metals. 
The unity of two or more elements. 
Being insistent and consistent; also a term to be 

used in a problem which never varies. 
The change from one state to another. 
A body larger at one end than at another; usually 

applied to a form which is cylindrical in shape 

but tapering, from end to end. 
The bringing togetlier of particles, or molecules. 
A spiral form of winding, like a watch spring. 
A form of winding, like a string wound around a 

bobbin. 
Applied generally to the quality of material which 

will carry a current of electricity; also a quality 

of a material to convey heat. 
The force by which the molecules of the same kind 

are held together. 
A line which is equidistant at all points from a 

center. 
Held within certain bounds. 
Molecular or atomic form. 
To come together from all points. 
A surface which is depressed or sunken. 
A surface which is raised, or projects beyond the 

surface of the edges. 
One of the elements in a problem or in a compound. 
A number indicating the degree or quality possessed 

by a substance. An invariable unit. 
A body having six equal sides. 



GLOSSAEY 



199 



Cross-section. 

Cross slide. 

Contiguous. 
Cone plate. 
Countersink. 
CoUet. 

Countershaft. 



Conducive. 
Corundum. 

Cold chisel. 

Combustion. 
Conjunctively. 
Comparatively. 
Cotter. 
Dead center. 

Depicting. 

Deodorant. 

Developer. 

Decimeter. 

Decameter. 

Defective. 

Diaphragm. 



A term used to designate that line which is at right 
angles to the line running from the view point. 

The metal plate on a lathe which holds the tool post, 
and which is controlled, usually, by a screw. 

Close to; near at hand. 

That part in a lathe which covers the cone pulleys. 

The depression around a bore. 

A collar, clutch or clamping piece, which has jaws 
to hold a bar or rod. 

A shaft which has thereon pulleys or gears to con- 
nect operatively with the gears or pulleys on a 
machine, and change fhe speed. 

Tending to; promotive of a result. 

An extremely hard aluminum oxide used for pol- 
ishing. 

A term applied to an extremely hard chisel used for 
cutting and chipping metal. 

The action or operation of burning. 

Acting together. 

Similitude or resemblance, one with another. 

A key to prevent a wheel turning on its shaft. 

A term used to designate the inoperative point of 
the crank. 

Showing; setting forth. 

A substance which will decompose odors. 

A chemical which will bring out the picture in mak- 
ing the film or plate in photography. 

The length of one-tenth of a meter in the metric sys- 
tem. 

The length of ten meters in the metric system. 

Not perfect; wrong in some particular. 

A plate, such as used in a telephone system, to receive 

and transmit vibrations. 



200 PEACTICAL MECHANICS FOE BOYS 



Dissolving. 
Division plate. 

Dispelled. 

Disinfectant. 

Diametral 

pitch. 
Dimension. 
Ductility. 

Dividers. 

Diverge. 
Drift. 

Drill stock. 

Duplex. 

Dynamite. 

Dynamometer. 
Eccentric. 
Echoes. 
Effervesce. 

Efficiency. 
Ellipse. 

Electrolytic. 



Elasticity. 



To change from a solid to a liquid condition. 

A perforated plate in a gear-cutting machine, to aid 
in dividing the teeth of a wheel. 

To drive away or scatter. 

A material which will destroy harmful germs. 

The number of teeth in a gear as calculated on tho 
pitch line. 

Measurement; size. 

That property of metal which permits it to be drawn 
out, or worked. 

An instrument, like a compass, for stepping off meas- 
urements, or making circles. 

Spreading out from a common point. 

A cutting tool foi smoothing a hole in a piece of 
metal. 

The tool for holding the cutting bit. 

Two ; double. 

An explosive composed of an absorbent, like earth, 
combined with nitro-glycerine. 

An instrument for measuring power developed. 

Out of center. 

The reflection of sound. 

The action due to the unity of two opposite chem- 
icals. 

The term applied to the quality of effectiveness. 

A form which is oblong, or having a shape, more or 
less, like the longitudinal section of an egg. 

The action of a current of water passing through a 
liquid, and decomposing it, and carrying elements 
from one electrode to the other. 

The quality in certain substances to be drawn out 
of their normal shape, and by virtue of which they 
will resume their original form when released. 



GLOSSAKY 



201 



Embedded. 
Emerge. 
Emphasize. 
Emery. 



Enormous. 

Enunciated. 

Equalization. 

Eradicator. 
Escapement. 



Essential. 

Expansion. 

Equidistant. 

Evolved. 

Facet. 

Facilitated. 

Flux. 

Fluid. 

Flour emery. 
Flexible. 

Float cut. 

Flexure. 
Foot pound. 



To be placed within a body or substance. 

To come out of. 

To lay particular stress upon. 

A hard substance, usually some of the finely divided 
precious stones, and used for polishing and grind- 
ing purposes. 

A large amount; great in size. 

Proclaimed; given out. 

To put on an even basis; to make the same compar- 
atively. 

To take out ; to cause to disappear. 

A piece of mechanism devised for the purpose of giv- 
ing a uniform rate of speed to the movement of 
wheels. 

The important feature; the principal thing. 

To enlarge; growing greater. 

The same distance from a certain point. 

Brought out of; the result of certain considerations. 

A face. 

Made easy. 

Any substance which will aid in uniting material un- 
der heat. The act of uniting. 

Any substance in which the particles freely inter- 
change positions. 

Emery which is finely ground. 

The quality of any material which will permit bend- 
ing, and return to its normal position. 

The term when applied to a tool where the cut is an 
easy one. 

The springing yield in a substance. 

A unit, usually determined by the number of pounds 
raised one foot in one second of time. 550 pounds 
raised one foot in one second of time, means so 
many foot pounds. 



202 PEACTICAL MECHANICS FOR BOYS 



Formulate. 

Focus. 

Foci. 

Formation. 

Fractured. 

Fundamental. 

Fulcrum. 

Fusion. 

Fusible. 
Fulminate. 

Gamut. 

Gear. 

Gelatine. 

Globular. 

Glazed. 

Graphite. 

Graduated. 

Grinder. 

Gullet. 

Harmonizing. 

H. P. 

Helico. 

Hexagon. 

Heliograph. 

Horizontal. 

Hydrogen. 



To arrange; to put in order from a certain consider- 
ation of things. 

The center of a circle. 

One of the points of an ellipse. 

The structure of a machine or of a compound. 

Broken. 

Basis; the first form; the original structure. 

The resting place for a lever. 

Melting. The change of a metal from a solid to a 
liquid state by heat. 

That which is capable of being melted. 

A substance that will ignite or explode by heat or 
friction. 

The scale of sound or light, or vibrations of any kind. 

A toothed wheel of any kind. 

A tasteless transparent substance obtained from ani- 
mal tissues. 

Having the form of a globe or ball. 

Having a glossary appearance. 

A metallic, iron-black variety of carbon. 

To arrange in steps ; a regular order or series. 

Any mechanism which abrades or wears down a sub- 
stance. 

The curved notches or grooves between projecting 
parts of mechanism. 

To make the various parts act together in unison. 

The symbol for horse power. 

A form resembling that of the threads of a screw. 

Six-sided. 

The system of signaling by using flashlights. 

Things level with the surface of the earth; like the 
surface of water. 

The lightest of all the elements. A tasteless, colorless 
substance. 



GLOSSAEY 



203 



Import. 

Impulse. 

Impact. 

Invariably. 

Inertia. 



Intersect. 

Interval. 

Intensity. 

Interstices. 

Intermediate. 

Intermeshing. 

Internal. 

Inability. 

Initial. 

Increment. 

Inference. 

Insoluble. 

Indentations. 

Induction. 

Inflammable. 

Inclining. 

Inconsequen- 
tial. 

Isometric. 

Jaw. 

Joule. 

Key-way. 



To bear, or convey as a meaning. 

The application of an impelling force. 

A collision; striking against. 

Constant; without failing. 

The quality of all materials to remain at rest, or to 
continue in motion, unless acted on by some exter- 
nal force. 

To divide at a certain point. The crossing point of 
one line over another. 

A space; a distance between. 

Strained or exerted to a high degree. 

The spaces between the molecules or atoms in a sub- 
stance. 

Between. 

The locking together of gear wheels. 

That which is within. 

Unable to perform or do. 

The first; at the start. 

One of the parts which go to make up the whole. 

Drawing a conclusion from a certain state of things. 

A substance which cannot be liquefied by a liquid. 

Recesses, or cut-out parts or places. 

The movement of electricity through the air from one 
conductor to another. 

That which will burn. 

At an angle; sloping. 

Not of much importance. 

That view of a figure which will give the relation 
of all the parts in their proper proportions. 

The grasping part of a vise, or other tool. 

The practical unit of electrical energy. 

A groove in a shaft and in the hub of a wheel, to re- 
ceive therein a locking key. 



47 



204 PEACTICAL MECHANICS FOE BOYS 



Kilowatt. 
Kinetic. 
Lacing. 
Lap. 



Lapping. 
Lacquer. 
Lazy-tongs. 

Levigated. 

Litharge. 

Longitudinal. 

Luminous. 

Magnet. 

Manipulation. 
Mandrel. 

Manually. 
Margin. 
Malleability. 
Magnetism. 

Major axis. 
Minor axis. 
Meridian. 

Metric. 

Micrometer. 
Milling 
machine. 

Miter. 



A unit of electrical power; one thousand watts. 

Consisting of motion. 

The attaching of the ends of a belt to each other. 

A tool, usually of copper or lead, on which flour em- 
ery is spread, with oil, and used to grind out the 
interior of cylinders. 

The act of using a lap to grind out cylinders. 

A varnish for either wood or metal. 

A form of tool, by means of which a long range of 
movement is attainable, and great grasp of power. 

Reduced to a fine powder. 

A form of lead used in paints for drying purposes. 

Lengthwise. 

That which has the capacity to light up. 

A bar of iron or steel that has electricity in it ca- 
pable of attracting certain metals. 

Capable of being handled. 

The revolving part of a lathe; a rod or bar which 
turns and carries mechanical elements thereon. 

Operated by hand. 

An edge. 

Softness. The state of being formed by hammering. 

A quality of certain metals to receive and hold a 
charge of electricity. 

The measurement across the longest part of an ellipse. 

The distance across the narrowest part of an ellipse. 

The time when the sun crosses the middle of the 
heavens; midday. 

Measure; a system which takes the unit of its meas- 
urement from the circumference of the earth. 

A tool for measuring small spaces or intervals. 

A large tool for the purpose of cutting gears and 
grooves or surfaces. 

A meeting surface between two right-angled pieces. 



GLOSSAEY 



205 



Momentum. That quality of matter which is the combined en- 
ergy of mass and speed. 

Molecular. Any substance that is made up of any particles; the 

component elements in any substance. 

Modifications. Changes; improved arrangements. 

Multiplicity. Many; numerous; a large quantity. 

Mutilated. As applied to a gear, one in which certain teeth are 

removed. 

Nautical. Marine; applied to shipping, and the like. 

Neutralizes. Any substance, like a chemical, which, when added 
to another chemical, will change them both. 

Nitro- An explosive made from glycerine and nitrogen, 

glycerine. 

Oblique. At an angle; inclined. 

Obliterate. To wipe out. 

Obvious. That which can be seen; easily observed. 

Obtuse. A blunt angle ; not noticeable. 

Odophone. An instrument for determining and testing odors. 

Olfactory. The nerves of the sense of smell. 

Orifice. An opening; a hole. 

Oscillation. A movement to and fro, like a pendulum. 

Oxygen. The most universal gas, colorless and tasteless ; is 

called the acid-maker of the universe and unites 
with all known substances, producing an acid, an 
alkali, or a neutral compound. 

Oxidizing. To impart to any substance the elements of oxygen. 

Oxide. Any substance which has oxygen added to it. 

Pallet. A part of a tooth or finger which acts on the teeth 

of a wheel. 

Parallel. Lines or sides at equal distance from each other from 

end to end. 

Paraffine. A light-colored substance, produced from refined pe- 

troleum. 



206 PEACTICAL MECHANICS FOE BOYS 



Perimeter. The outer margin of a wheel ; the bounding line of any 

figure of two dimensions. 
Periphery. The outer side of a wheel. 

Peon. The nailing end of a hammer. 

Persistence. That quality of all matter to continue on in its 

present condition. 
Perpendicular. A line drawn at right angles to another. 
Perpetual. Without end. 

Perspective. A view of an object which takes in all parts at one 

side. 
Physically. Pertaining to the body. 
Phonautograph. An apparatus for recording sound. 
Phonograph. An apparatus for taking and sending forth sound 

vibration. 
Phenomena. Any occurrence in nature out of the ordinary. 
Pitman. The rod or bar which connects the piston and crank. 

Pivot. A point or bar on which anything turns. 

Pinion. A small toothed wheel. 

Pitch. The number of vibrations. The term used to give 

the number of teeth in a wheel. 
Pitch diameter. The point from which the measurements are made in 

determining the pitch. 
Pivoted. A bar, lever, or other mechanical element, arranged 

to turn on or about a point. 
Plastic. A substance in such a state that it may be kneaded 

or worked. 
Planer. A large tool designed to cut or face off wood or 

metal. 
Porosity. The quality in all substances to have interstices, or 

points of separation, between the molecules. 
Potential. The power. 

Properties. The qualities possessed by all elements. 

Projecting. The throwing forward. The sending out. 



GLOSSAEY 



207 



Promulgated. Put forth; enunciated. 

Protractor. A mechanic's and draughtsman's tool by means of 

which angles may be formed. 

Promote. To carry forward in a systematic way. 

Precision. Work done with care; observing correct measure- 

ments. 

Prony brake, A machine for determining horse power. 

Punch. A small tool to be struck by a hammer in order to 

make an impression or indentation. 

Quadrant. One-fourth of a circle. 

Quadrant A plate on which are placed lines and numbers indi- 

plate. eating degrees. 

Quadruplex. A term to designate that system of telegraphy in 
which four messages are sent over a single wire at 
the same time. 

Ratchet. A wheel having teeth at certain intervals to catch 

the end of a pawl or finger. 

Ratchet brace. A tool to hold a drill, having a reversible ratchet 
wheel. 

Rasp cut. A cut of a file which is rough, not smooth. 

Rake. The angle or inclination of the upper surface of the 

cutting tool of a lathe. 

Reverse. To turn about ; in the opposite direction, 

Reciprocating. To go back and forth. 

Revolve. To move in an orbit or circle, as a meryy-go-round. 

Reciprocity. lo give back in like measure. 

Reflection. The throwing back from a surface. 

Resonance. The quality of vibration which adds to the original 

movement, and aids in perpetuating the sound. 

Refraction. The quality of light which causes it to bend in pass- 

ing through different substances. 

Reducing. Bringing it down to a smaller compass. 

Rectilinear. A straight line. 



208 PEACTICAL MECHANICS FOE BOYS 



Retort. 

Reamer. 

Regulation. 

Refractory. 

Recess. 

Rocking. 

Rotate. 
Rosin. 
Roughing. 
Saturated. 

Scribe. 
Screw plate. 

Section lining. 

Shaper. 

Shrinkage. 

Slide rest. 

Sonorous. 

Slotted. 

Solvent. 

Spelter. 

Soldering. 

Spindle. 

Solidity. 

Spur. 

Socket. 

Sprocket. 



A furnace of refractory material to take high heat. 

A tool designed to enlarge or to smooth out holes. 

To do things in an orderly way; a system which sets 
forth certain requirements. 

Difficult to work, and not easily fused. 

A hole, or a depression. 

A lever which rotates only part way and then moves 
in the opposite direction. 

A spindle which turns round. Compare revolve. 

Certain gums; particularly the sap of pine trees. 

The taking off of the first coating with a tool. 

A soluble substance which cannot be further dis- 
solved by a liquid. 

To mark with a tool. 

A tool which has within it means for adjusting dif- 
ferent cutting tools. 

The marks made diagonally across drawings to indi- 
cate that the part is cut away. 

A large tool for surfacing off material, cutting 
grooves, and the like. 

The term applied to metals when cast, as all will be 
smaller when cold than when cast in the mold. 

The part of the lathe which holds the tool post. 

Having the quality of vibration. 

Grooved, or channeled. 

That which can be changed from a solid by liquids. 

A combination of zinc and copper. A hard solder. 

Uniting of two substances by a third, with heat. 

A small shaft. 

The contents of a body. 

The larger of two intermeshing gears. 

A depression or hole. 

Teeth in a wheel to receive a chain. 



GLOSSARY 



209 



Spiral. A form wound like the threads of a screw. 

Spectroscope. An instrument by means of which the light from an 
object may be analyzed. 

Stud. A small propecting part or pin. 

Stylus. A pointed pin. 

Stethoscope. An instrument for detecting minute sound waves. 

Spectrum. The divided light elements shown on a screen. 

Structural. The form or manner in which a piece of mechanism 

is made. 

Surface A true surface made of metal, used as a means of de- 

plate, termining evenness of the article made. 

Sulphate. Any substance which is modified by sulphuric acid. 

Substitute. An element or substance used for another. 

Superposed. One placed above the other. 

Swage. tool for the purpose of changing the form in a ma- 

terial. 

Swivel. A point on which another turns. 

Surfacing. Taking off the outer coating or covering. 

Tap. A small drill. 

Tapering. An object with the sides out of parallel. 

Tangential. A line from the periphery of a circle which pro- 
jects out at an angle. 

Tension. The exertion of a force. 

Tenacity. The property of a material to hang together. 

Tempering. Putting metal in such condition that it will be not 
only hard but tough as well. 

Technical. Pertaining to the strict forms and terms of an art. 

Texture. That of which the element or substance is composed. 

Threads. The ridges, spiral in form, which run around a bolt. 

Theoretically. The speculative form or belief in a subject. 

Tinned. The term applied to the coating on a soldering iron 

with a fluxed metal. 

Tines. Small blades. 



210 PEACTICAL MECHANICS FOE BOYS 



Torsion. 

Tommy. 

Transmitting. 
Trammel. 
Traction. 
Tripping. 



Triangular. 
Transverse. 
Undercut. 
Undulatory. 

Unit. 

Unison. 

Unsized. 



Vaporizing. 

Variation. 

Verge. 

Vertical. 
Velocity. 
Vitascope. 

Vibration, 



Vocation. 



The force exerted around an object, like the action of 
a crank on a shaft, 

A lever to be inserted in a hole in a screw head for 
turning a screw. 

Sending forth; to forward. 

A tool for the purpose of drawing ellipses. 

Drawing; pulling power. 

A motion applied to a finger, which holds a pivoted 
arm, whereby the latter may be swung from its 
locked position. 

Having three sides and three angles. 

Across; at right angles to the long direction. 

A wall of a groove or recess which is sloping. 

A wave-like motion, applied generally to light and 
electricity. 

A base for calculating from. 

Acting together ; as one. 

Generally applied to the natural condition of paper 
or fabric which has no glue or other fixing sub- 
stance on it. 

To change from a liquid or solid to a gas. 

Changing into different conditions; unlike forms. 

The edge; usually applied to the shoulder of a watch 
spindle, particularly to the escapement. 

Up and down. The direction of a plumb line. 

The speed of an article through space. 

An instrument for determining the rate of vibration 
of different substances. 

The movement to and fro of all elements, and by 
means of which we are made sensitive of the dif- 
ferent forces. 
The business or the calling of a person. 



GLOSSAEY 211 

Warding. The act of cutting a projection or guard, such as is 

usually found on the insides of locks, and the cor- 
respondent detent in the key. 

Watt. In electricity the unit of the rate of working in a cir- 

cuit. It is the electro-motive force of one volt and 
the current intensity of one ampere. 



INDEX 



(Figures indicate the pages) 



Acetone, 165. 
Acid, 119, 120, 156, 168. 
Acid, Acetic, 165. 
Acid, Carbolic, 166. 
Acid, Hydrofluoric, 170. 
Acid, Muriatic, 119. 
Acid, Nitric, 168, 169, 171, 173. 
Acid, Oxalic, 172. 
Acid, Pyrogallic, 172. 
Acid, Sulphuric, 169. 
Acoustics, 87, 157. 
Adhesives, 162. 
Affinity, 83, 86. 
Agate, 82. 
Air, 84. 
Alcohol, 165, 166, 169, 170, 176, 

183. 
Alloy, 81, 115, 116, 118, 119, 

149, 175. 
Alum, 149, 166, 172. 
Aluminum, 38, 41, 42, 60, 82, 

149, 164, 166, 169, 170, 174, 

175, 176, 184. 
Amalgams, 149. 
Amber, 170. 
Ambergris, 159. 
Ammonia, 166, 170. 
Ammonium Nitrate, 185. 



Ammonium Sulphate, 168, 171. 

Analysis, 93. 

Analyzed, 159. 

Angle cutting, 30. 

Angle plate, 10. 

Angles, 31, 39, 59, 72, 102, 103, 

104, 107, 152. 
Aniline, 176. 
Annatto, 168, 170. 
Annealing, 112, 113, 114, 115. 
Annular, 67. 
Anvils, 14, 15, 16. 
Apothecaries, 180. 
Application for patent, 191. 
Arbor, 14. 
Arc, 146. 
Area, 148. 
Armature, 153. 
Arrow root, 15§. 
Artisan, 112. 
Asbestos, 168. 
Asphalt, 14, 175. 
Assign, 191, 193. 
Assignment, 192. 
Atom, 157. 
Attraction, 86. 
Avoirdupois, 180. 
Axis, 106, 127. 
Axis, major, 105. 
Axis, minor, 105, 106. 



11 



213 



214 PEACTICAL MECHANICS FOE BOYS 



Ball, 75. 

Ball and Socket, 74. 

Balsam Peru, 168, 189, 173. 

Barium Chloride, 176. 

Bark, soap, 165. 

Barleycorn, 143. 

Barrel, 149. 

Base line, 102. 

B. T. U., 180, 181. 

Beeswax, 174. 

Bell metal, 164. 

Belt, 68. 

Belt, Lacing, 68, 69. 

Bench, 77, 104. 

Benzine, 169. 

Benzol, 173. 

Bevel, 69, 70, 125, 126. 

Bibb, 70. 

Bismuth, 118. 

Bisulphate of carbon, 185. 

Bisulphate of sodium, 172. 

Bitt, 28, ^2. 

Bitts, machine, 38. 

Bitts, plain, 38. 

Bitts, round-nosed, 38. 

Bitts, setting, 39. 

Bitts, square, 38. 

Black, ivory, 171. 

Blade, hack-saw, 35, 36. 

Bloodstone, 173. 

Blue black, 173. 

Boiler, 150, 152. 

Boiler, compound, 161. 



Bolt, 75. 

Bolt, anchor, 7. 

Boracic acid, 168. 

Borax, 168, 176. 

Brass, 41, 43, 44, 168, 170, 174, 

175, 176, 184. 
Bronze, 150, 164, 173, 176, 184. 
Bulk, 134. 



Calcium, 166. 

Calcium Chloride, 185. 

Calipers, 37, 45, 49, 66. 

Calls, 160. 

Camphor, 164, 166, 175. 

Canada balsam, 172. 

Capillary attraction, 86, 87. 

Carbolic acid, 166. 

Carbon, 113. 

Carbonate, 150. 

Carbonate of soda, 116, 172. 

Carbon paper, 171. 

Cardinal, 102. 

Carbolized, 169. 

Cast iron, 42, 64, 81, 169, 183. 

Caustic soda, 106, 150. 

Caveat, 190. 

Celluloid, 164. 

Cement, 162, 163. 

Centaire, 146. 

Center, dead, 78. 

Center line, 41. 

Centering, 111. 



INDEX 



215 



Centers, 62. 
Centimeter, 146. 
Centrifugal, 85. 
Centripetal, 85. 
Ceresine, 174. 
Chalk, 165. 
Channel, 71. 
Charcoal, 113, 167, 185. 
Chemical, 83, 157, 180. 
Chisels, drifting, 32. 
Chisels, key-way, 32. 
Chisels, square, 53. 
Chlorate of potash, 167, 169, 

170. 
Chloride of lime, 165. 
Chloride of platinum, 173. 
Chloride of tin, 119. 
Chloride of zinc, 163, 176. 
Chloral hydrate, 169. 
Chloroform, 163. 
Chromate of potash, 169, 170. 
Chuck, 54. 

Chuck, independent, 64. 
Chuck, universal, 64. 
Circle, 96, 106, 107, 111, 148, 

169. 
Circuit, 153, 154. 
Circular pitch, 122, 124, 125. 
Circumference, 148. 
Citric, 165. 
Clamp, 77. 
Clay, 164, 165. 
Clearance, 30, 38, 40. 
Clef, 159. 



Clutches, 74. 

Coal, 139. 

Coherer, 154. 

Cohesion, 50, 83. 

Color, 92, 157, 161. 

Combination, 136, 156. 

Commutator, 155. 

Compass, 106. 

Compound, Welding, 117. 

Compression, 77, 84. 

Compressibility, 84. 

Concave, 92, 93. 

Concentric, 88. 

Conception, 191. 

Conductivity, 82. 

Conductor, 82, 88. 

Cone, 70. 

Conveyor, 91. 

Convex, 92, 96. 

Convolute, 78. 

Copal varnish, 163. 

Copper, 45, 60, 112, 118, 164, 

170, 173, 174, 184. 
Corpuscular, 91. 
Corundum, 27. 
Crank, 70, 76, 78, 135. 
Cream of Tartar, 165, 174. 
Crown wheel, 70. 
Cryolite, 176. 
Cube, 97, 98, 107, 149. 
Current, 154, 158. 
Curve, 104. 
Cutter, side, 30. 
Cutting tool, 171. 



216 PRACTICAL MECHANICS FOR BOYS 



Cyanide of Potassium, 170. 
Cylinder, 39, 40, 66, 80, 90, 
134, 135, 136. 



Decameter, 146. 

106, 109, 183, 187. 
Decimeter, 146. 
Declaration of Interference, 

190. 
Degree, 40, 101, 102, 103, 104, 
Deodorant, 166. 
Dessertspoon, 151. 
Detail, paper, 111. 
Develop, 157. 
Developer, 172. 
Dextrine, 169. 
Diameter, 52, 126, 140, 143, 

144, 148, 149, 150. 
Diameter, inside, 122. 
Diameter, outside, 122. 
Diameter, pitch, 122. 
Diametral pitch, 123, 124. 
Diamond, 81, 149. 
Diaphragm, 90, 153, 154. 
Disinfectant, 166. 
Disks, 49, 50, 67, 71, 74, 75, 82, 

91, 95, 96, 105. 
Disk shears, 90, 153, 154. 
Distilled, 144, 151. 
Diverge, 91. 
Divided, 192. 
Dividers, 45, 52, 62, 63. 
Dogs, 77. 



Dollar, 144. 
Drams, 180. 
Drawing, 95, 97, 101, 108, 109, 

129, 191. 
Drill, 30, 31. 
Drilling Machine, 43. 
Driver, 73. 
Dry measure, 182. 
Ductility, 80, 81. 
Dynamite, 167. 
Dynamo, 155. 

E 

Eccentric, 78. 
Echo, 89. 
Effervesce, 119. 
Elastic, 91. 
Elasticity, 87, 112. 
Electrical, 82, 153, 154, 155. 
Electric current, 182. 
Electric curves, 182. 
Electricity, 78, 84, 93. 
Electrolytic, 149. 
Electro-motive force, 154. 
Ellipse, 72, 104, 105, 106, 107. 
Emery, 27, 36, 150, 165, 166, 

167. 
Emery cloth, 55. 
Emery wheel, 22. 
Energy, 140. 
Engine, 45, 78, 134. 
Equalization, 82. 
Escapement, 72. 
Ether, 91, 169. 



INDEX 



217 



Expansion, 93. 
Explosions, 156, 167. 

F 

Facet, 52. 

Fahrenheit, 148, 186. 

Feed, longitudinal, 66. 

Feed, transverse, 66. 

Ferric chloride, 166. 

Filament, 160. 

File, cross, 57. 

File, cutter, 56. 

File, double end, 57, 58. 

File, equalizing, 57. 

File, float cut, 57. 

File, half round, 56. 

File, holding, 59. 

File, middle, 57. 

File, movement, 59, 60. 

File, pinion, 56. 

File, rasp cut, 57. 

File, rat-tail, 56. 

File, rough, 57. 

File, round, 56. 

File, saw, 56. 

File, second cut, 57. 

File, shearing cut, 59. 

File, slitting, 57. 

File, smooth, 57. 

File, square, 56. 

File, triangular, 56. 

Files, 36, 48, 50, 52, 53, 56, 59, 

60, 114, 167, 168. 
Files, Hexagon, 51, 52. 
Filing, 52, 53, 54, 55, 56, 61. 



Filter paper, 171. 

Fire clay, 164, 165. 

Fish oil, 171, 176. 

Fire proof, 168, 171. 

Flexure, 79. 

Floor dressing, 168. 

Fluid, 165. 

Fluor spar, 116. 

Fluxes, 115, 116, 118, 176. 

Focal, 106, 107. 

Focus, foci, 105. 

Foot, 145. 

Foot lathe, 78. 

Foot pounds, 139, 140, 143, 

181. 
Force, 156, 157. 
Forge work, 116. 
Forges, 164. 
Formic acid, 168. 
Formula, 162. 
Freezing mixtures, 185. 
Friction, 70, 171. 
Fuel, 134, 181. 
Fulcrum, 76, 128, 129. 
Fulminate, 167. 
Furlong, 181. 
Furniture, 164. 
Fusible, 116. 
Fusion, 115. 

G 

Gage, 45, 46, 47, 148. 
Gage surface, 84, 87, 94. 
Gallon, 144. 
Gas stove, 166. 



218 PRACTICAL MECHANICS FOR BOYS 



Gear, 42, 69, 70, 74, 121, 122, 
123, 125, 126, 133, 171. 

Grear, bevel, 70. 

Grear, friction, 70. 

Gearing, 121. 

Gear, miter, 70, 123, 124, 125, 
126. 

Gear, mutilated, 72. 

Gear, spur, 122. 

Gelatine, 162, 173. 

Geranium, 169. 

German silver, 82. 

Giant powder, 167. 

Glass, 84, 92, 112, 163, 169. 

Glauber salts, 164. 

Glazing, 72. 

Glue, 159, 162, 168. 

Glycerine, 115, 162, 165, 176. 

Gold, size, 173. 

Grain, 81. 

Grains, 180. 

Graphite, 171, 175. 

Gravity, 85. 

Grinder, 27. 

Grinder wheels, 36. 

Grindstones, 22, 36, 149. 

Groove, 71, 76. 

Gum, 163. 

Gum arable, 163. 

Gum lac, 170. 

Guncotton, 188. 

Gunpowder, 168. 

Hack-saw, 34, 35, 36. 

Hack-saw blade, 35, 36. 



Hammer, 81, 115, 117. 
Handy tables, 178. 
Hardness, 81, 114, 115. 
Harmony, 154, 158, 159, 160. 
Head, 135. 
Heat, 93, 186. 
Hectare, 146. 
Hectometer, 146. 
Helical, 77. 
Helical, double, 77. 
Helix-volute, 77. 
Hexagon, 51, 52. 
Horizontal, 97, 102, 105. 
Horse ]rower, 139, 143, 146, 148, 

186, 181. 
Hours, H. P., 186, 187. 
Hours, kilowatt, 186, 187. 
Hub, 74. 

Hub, key-way, 125. 
Hydrochloric acid, 172. 
Hydrofluoric acid, 149. 
Hydrogen, 83. 

I 

Inches, 181. 

Inclined plane, 123, 128. 

Indentation, 154. 

Indicator, speed, 140. 

Induction, 154. 

Inertia, 84. 

Injector, 152. 

Inks, 110. 

Inside diameter, 122. 

Instrument, 158, 159. 

Internal, 86, 102. 



INDEX 



219 



International, 193. 

Invention, 152, 153, 161, 188, 

189, 190, 192, 193, 194. 
Inventor, 157, 181, 190. 
Iron, 42, 63, 155, 162, 165, 169, 

175, 184. 
Iron, wrought, 42, 82, 112. 
Isinglass, interference, 190. 
Isometric, 107. 
Ivory, 84. 
Ivory, black, 171. 

J 

Japan wax, 174. 
Joint, ball and socket, 74. 
Joint, universal, 70. 
Joule, 174. 

K 

Kerosene, 150, 165, 171. 
Key, 158. 
Key- way, 125. 
Kilometer, 146. 
Kilowatt, 186, 187. 
Kilowatt hour, 186, 187. 
Kinetic, 140. 



Lacquer, 170. 

Lampblack, 167, 175. 

Lapping, 166, 167. 

Lathe, 28, 39, 42, 45, 64, 65, 67, 

104, 171. 
Lathe speed, 34. 
Lathe tool, 33, 39. 
Lavender, 168. 
48 



Lead, 60, 118, 163, 164, 175. 

Leather, 162, 163. 

Level, 87. 

Lever, 73, 75, 76, 128, 129, 130, 

131, 132, 133, 140, 153. 
Leverage, 143. 
Licenses, 189. 
Light, 100. 
Lime, 173. 

Linear measure, 181. 
Lines, 95, 99, 110. 
Lines, section, 84. 
Linseed, 162. 

Linseed oil, 149, 174, 175. 
Liquid measure, 182. 
Liquids, 84. 
Litharge, 163. 
Long measure, 181. 
Lubricant, 171. 
Luminous, 91. 
Lycopodium, 169. 

M 

Machine, 26. 
Magnesium, 166, 
Magnesium sulphate, 169. 
Magnet, 153. 
Magnetism, 93. 
Major axis, 105. 
Malleability, 81. 
Malleable, 112. 
Mandrel, 66, 76. 
Manganese, 163. 
Marble, 162. 
Mass, 85. 



220 PEACTICAL MECHANICS FOE BOYS 



Mastic, 169. 

Measure, 139, 140, 143, 151. 
Measure, liquid, 182. 
Measure, long, 181. 
Measurement, 145. 
Measure, paper, 182. 
Measure, solid, 82. 
Measure, square, 181. 
Membrane, 90. 
Mercuric chloride, 166. 
Mercury, 94, 114, 183. 
Meridian, 145. 
Metric, 144, 145, 146. 
Metrical, 145. 
Micron, 146. 
Microscope, 91. 
Millimeter, 146. 
Milling machine, 26. 
Minor, 164. 
Minor axis, 105, 106. 
Miter, 146. 

Miter gear, 123, 124, 125, 
Molecular, 82, 117. 
Molecular forces, 82. 
Molecules, 83, 84, 146. 
Momentum, 83, 85. 
Motion, 84, 156. 
Motor, 136, 155. 

N 

:Neat's Foot oil, 168. 
Neroli, 168. 
Nickel, 164. 
Nitrate of copper, 174. 



Nitrate of potash, 167. 

Nitrate of silver, 174, 

Nitric acid, 162, 168, 169, 171, 

173. 
Nitro-glycerine, 167, 185. 



Oath, 193. 
Octave, 159. 
Odophone, 159. 
Odor, 159. 
^Oil, 83, 87, 167, 171. 
Oil eradicator, 166. 
Oleonaptha, 171. 
Oscillations, 90, 157. 
Ounce, 180. 
Outlines, 99. 
Oxalic acid, 172. 
Oxidation, 117. 
Oxide, 117, 163. 
Oxidizing, 116. 
126. Oxygen, 83, 119. 

P 

Palm oil, 171. 

Paper, 168, 171. 

Paraffine, 168, 171. 

Parallel, 91, 100, 121. 

Paris blue, 172. 

Paste, 163, 173. 

Patents, 188, 189, 190, 192, 194. 

Pawl, 73, 76. 

Pendulum, 73. 

Parting tools, 28. 

Perimeter, 73. 



INDEX 



221 



Periphery, 73. 

Permanganate of potash, 178. 
Perpendicular, 105. 
Perpetual motion, 128. 
Perspective, 97, 106, 107. 
Petroleum, 168. 
Phenomenon, 91, 153. 
Phonautograph, 90. 
Phonograph, 91, 154. 
Phosphorus, 149. 
Photographer, 157, 172. 
Piano, 158, 159. 
Pinion, 57, 74. 
Pitch, 121, 125, 156. 
Pitch, circle, 122, 124, 125. 
Pitch, diameter, 123, 124. 
Pitch, line, 123, 124, 127. 
Pitman, 70. 
Pivots, 70, 130. 
Planer, 26, 50, 51, 126. 
Plaster, 173. - 
Plaster of Paris, 150, 174. 
Plate, 73. 
Plates, 50. 
Plating, 173. 
Platinum, 81. 
Plumbago, 173. 
Poles, 155. 
Polishes, 174. 
Position, 102. 
Potash, 116, 167. 
Potash, prussiate, 113. 
Potassium cyanide, 170. 
Potassium nitrate, 167. 



Pound, 145, 157, 180. 

Power, 128, 129, 130, 131, 133, 

134, 140, 158, 159, 186. 
Power, horse, 139, 140. 
Precision tools, 50. 
Preliminary statement, 191, 
Pressure, 134, 135, 137, 148, 

152. 
Prime mover, 134. 
Printing telegraph, 155. 
Prism, 92, 93. 
Protractor, 108, 109. 
Prussiate of potash, 113. 
Pulley, 68, 70, 73, 128, 133, 140, 

149, 150. 
Pulsation, 153. 
Pumice, 83. 

Pumice stone, 110, 175. 
Punch, 62, 63. 
Punch, centering, 62. 
Punch cutter, 24. 
Putty, 175. 

Q 

Quadrant, 102, 103. 
Quality, 157. 
Quarter, 180. 
Quartz, 182. 

R 

Racks, 73, 74. 

Radius, 52. 

Rake, 29, 30, 38, 42, 43, 45. 

Rainbow, 92. 

Ratchet, 77. 



V 



222 PRACTICAL MECHANICS FOR BOYS 



Ratchet brace, 77. 
Reciprocity, 82. 
Reflected, 92. 
Reflecting, 89. 
Reflection, 88, 91. 
Refraction, 92. 
Resin, 176. 

Resistance, 79, 82, 83. 
Resonance, 89. 
Rim, 96. 
Ring, 96. 
Rods, 180. 
Rosemary, 166. 
Royalty, 193. 
Rubber, 84, 163. 
Rule, 53. 

Rule, key-seat, 53, 54. 
Rust preventive, 175. 

S 

Saffro, 170. 

Sal ammoniac, 119, 162, 165, 

176, 185. 
Salt, 165, 170, 183, 185. 
Sandarac, 169, 176. 
Saw, 26, 64, 76. 
Saw, wabble, 76. 
Scale, 100, 101. 
Science, 157. 
Scraper, 50, 51. 
Scribe, 47, 53. 
Scruples, 180. 
Sealing wax, 176. 
Section lining, 103, 104, 110. 



Sense, 159. 

Sesame oil, 176. 

Shade, 96. 

Shading, 9<5, 110. 

Shaft, 68, 69, 70, 73, 74, 75. 

Shaft coupling, 74. 

Shaper, 26, 50, 51, 53. 

Shellac, 163. 

Side cutters, 30. 

Sienna, 168. 

Signals, 87. 

Silicate, 168. 

Silver, 82, 118, 164, 165, 180, 

183. 
Snow, 185. 
Soap, 105, 172. 
Soap spirits, 166. 
Soda, sulphate, 172. 
Sodium carbonate, 172. 
Sodium silicate, 168. 
Sodium sulphate, 172. 
Solder, 118, 175. 
Solder, hard, 118. 
Solder, soft, 118. 
Soldering, 116, 117, 119, 176. 
Solids, 84. 
Sonorous, 88. 
Sound, 87. 

Sounding-boards, 88. 
Spanish white, 168. 
Spectroscope, 90, 93, 161. 
Spectrum, 93. 
Speed, 43. 
Spelter, 118. 



INDEX 



223 



Sphere, 97. 

Spiral, 78. 

Sponge, 83. 

Spring, 72, 79, 176. 

Square, 48, 61, 63. 

Square combination, 24, 77, 81. 

Starcn, 162, 163, 164. 

Steel, 39, 40, 42, 44, 63, 79, 113, 

165, 168, 169, 170, 184. 
Stethoscope, 90. 
Stove polish, 174, 175. 
Straight edge, 61. 
Stylus, 90. 
Sugar, 163. 

Sulphate of copper, 174. 
Sulphate of potash, 115. 
Sulphate of soda, 172. 
Sulphur, 167, 183. 
Sulphuric acid, 165, 169, 175. 
Surfacing, 49, 50, 63. 



Table of weights, 178. 

Talcum, 169. 

Tallow, 176. 

Tannaform, 169. 

Taps, 45. 

Taste, 160. 

Teeth, 72. 

Telegram, 158. 

Telescope, 91, 92. 

Temperature, 82, 88, 114, 116, 

118, 119. 
Temperature table, 180. 



Tempering, 113, 114, 115, 176. 

Tenacity, 79, 80. 

Thread, 74. 

Thymol, 166. 

Tin, 98, 118, 175, 176, 184. 

Ton, 180. 

Tongs, 75. 

Tongs, lazy, 75. 

Tool, 22, 28, 40, 41, 61, 64, 71, 

108, 113, 175. 
Tool boring, 43. 
Tool cutting, 26, 29, 45, 64. 
Tool holder, 64. 
Tool hook, 28. 
Tool, hooked, 44. 
Tool knife, 28. 
Tool, parting, 28. 
Tool, roughing, 29. 
Tools, precision, 50. 
Torsion, 79. 
Toughness, 114, 115. 
Tracing cloth, 110. 
Tracing paper, 172. 
Traction, 79. 
Transmitting, 158. 
Transparent, 163. 
Transverse, 80. 
Treadle, 78. f 

Triangular, 97, 98. 
Tripping driver, 78. 
Turmeric, 170. 
Turpentine, 162, 165, 172, 173, 

174, 175. 
Turpentine, Venice, 176, 177. 



224 PEACTICAL MECHANICS FOR BOYS 



u 

Ultramarine, 171. 
Undivided, 192. 
Undulatory, 91. 
Unffuent, 114. 



Valve, 70. 

Vapor, 87. 

Varnish, 162, 170, 172, 175, 176. 

Vaseline, 165, 175. 

Velocity, 81, 87, 91. 

Vermilion, 177. 

Vertical, 97. 

Vibrate, 160, 161. 

Vibration, 87, 88, 90, 158. 

Vibratory, 91. 

Vinegar, 163, 170, 173. 

Violin, 159. 

Vise, 33. 

Vitascope, 90. 



W 

Water, 165, 166, 168, 172, 183, 

186, 187. 
Waterproof, 162, 163. 
Weight, 85. 
Weight of steel, 179. 
Weight, troy, 180. 
Welding, 115, 116, 117. 
Welding compound, 117. 
Wheel, 27, 72, 73, 85, 86. 
Whiting, 174. 
Workshop, 162. 
Wrench, 104. 



Yokes, 70, 76. 



Zinc, 118, 119, 164. 166, 175. 
Zinc chloride, 163. 



THE WONDER ISLAND BOYS 

Bt ROGER T. FINLAY 

Til rilling adventures by sea and land of two boys and 
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